user279: I'm preparing an opening repertoire for a small "open tournament" that will take place in a few weeks.
I think I'm quite decent at tactical play, and I like situations that give me the initiative - that is, attacking; or counterattacking when my opponent is attacking, since I can't stand rocky but passive defense. I also like games in which I can concentrate my attacks against specific targets (isolated pawn, opponent's blocked center, etc.).
So far, my repertoire is built this way:
with White: basically 1.e4

against 1...e5, Italian (all variations) and 2-Knights (all variations), 4-Knights (all variations), and some variations of the Russian. Perhaps I'll add some variations of the Scotch Game;
for 1...c5 I've studied some of the main lines of the Open Sicilian, the Alapin and the Closed Sicilian;
for 1...c6 (Caro-Kann) I have prepared the Advance Variation and some of the main lines;
against 1...e6 (French) I know the lines of the Advance Variation;

Against other defenses, I've simply studied the strategical ideas behind the most famous "lesser" defences (Scandinavian, Pirc, Nimzowitsch, etc.), and I plan to play natural moves without searching for "early confutation".
with Black:

against 1.e4 I think I know kinda well Sicilian Kan, Paulsen and Sveshnikov, and many variations of the French Defense;
against 1.c4 I usually play the Reverse-Sicilian, and sometimes the Symmetrical English.

But I cannot find a decent opening to play against 1.d4 (just a lesser opening, indeed xD). And this can be a problem also against 1.Nf3, due to the many transpositions.
I used to play the "Nimzo-Indian + Queen's Indian" pair, but recently I found that those openings do not suit my playing style, especially the Queen's Indian. I've looked something about the Slav Defense, but I'm really scared of the many transposition into Semi-Slav and Queen's Gambit Declined (and the study that lies behind!). And I'm even more scared of theory speaking of King's Indian and Gruenfeld.
So, does anyone know defenses that may suit my playing style with Black against 1.d4? Do you think that, if I fill this void, my repertoire is complete enough?

user18809: Because tactical complications often come with very sharp positions, a tactical opening often means a lot of theory. So, it would depend on your skill level and, more importantly, on how many hours you want to spend building your repertoire.
At a lower skill level, 1.e4 looks like a nice choice, but in fact it's not the only one! There is 1.f4, the King's indian attack, or maybe some d4, Nc3, Bg5, Qd3/d2, 0-0-0, e4 system that also allow for complicated tactical games and may not need such a deep study.
With Black you can try the Tarrasch Defence against 1.d4 (central isolated pawns will suit you perfectly) and 1...e5 against 1.e4
If you are a strong player and you can dedicate a long time to studying openings, I would definitely stick to 1.e4as White, playing the Open Sicilian, the Scotish Opening, the Panov Attack and probably 3.Nd2against the French (or even 3. exd5 exd5 4.c4)
When playing Black, the Sicilian Dragon appears to be the best choice to me (Najdorf or Taimanov are good alternatives). I'd choose the Grunfeld Defence against 1.e4. Knowing the main ideas in the Dutch Defence and the Closed Sicilian is also helpful when playing against 1.c4and 1.Nf3.
Finally, I would remark that we should distinguish "tactical player" from "attacking player". For instance, the King's Indian and the Closed Sicilian are great choices for an attacking player, but the attack often comes as a result of a deep comprehension of strategical principles, rather than just "brute force". That's what led me to suggesting the Dragon Sicilan rather than other lines like the Scheveningen.

user10233: Nimzo-Indian Defense hands down. Black scores well, it's aggressive in nature and gives you targets as Black to attack. I would not touch the Dutch, Benoni, King's Indian or the Slav with a 10-foot pole. Slow grinding games is not what you want.
Go All in with the Nimzo!

user1733: Usually if i'm playing black and and my opponent plays the Queens Gambit I'll attempt to play the Benko Gambit, a very aggressive opening. If that does not work I transpose into the Pirc. It's hard to fall into traps and things like that in the opening, which gives you a good middle game and to play chess.

user1312: The opening you should be considering is the Benoni Defence. All decent lines by white lead to highly tactical middlegames where both sides are constantly making short-term threats. For this reason it has been a favorite for attacking and tactical players who wanted to play for middlegame wins as black, for example: Mikhail Tal, Bobby Fischer, Veselin Topalov, and Vugar Gashimov.
Another good option to consider is the Benko Gambit; although perfect play by white probably wins, below the grandmaster level the active piece play it gives black should allow you take advantage of your preference for active middlegames.
I play the Grunfeld, but based on your description I might caution you against it. Playing the Grunfeld correctly requires extensive book knowledge, which for me has added up to memorization. Also can be difficult to book up on the Grunfeld, because you usually want to play the same moves regardless of what white does, but choosing the correct move order is critical. If your opponent is deeply booked as white against the Grunfeld, and most expert level 1. d4 players and up will be, is very easy as black to play moves out of order and wind up with a stable but uncomfortable middlegame position where you are just worse.
However, if lots of book study doesn't sound scary, then the Grunfeld is an excellent choice: you will regularly get equal but dynamic middlegames as black.
You didn't include your ELO so I'll throw this out: against 1. d4 there is an offbeat line that can be effective at the class level, which is the Budapest gambit (1. d4 Nf6 2. c4 e5?!). Strictly speaking it is almost definitely unsound, but it is a strict upgrade over the Englund (which is unplayable, frankly).

user4543: The Chigorin is a good opening for tactical players. As in the Sveshnikov the pawn structure is half fixed half dynamic if you know what I mean. Play 1...Nc6 by C. Wisneweski is the best book in my opinion. At some stage if you keep improving you will need a line against the Pirc as good players in open tournaments tend to know it quite well.

user7450: When choosing a black opening you have to come to grips with the thought that black (usually) has to make some concession in any chosen opening. 
When looking for my answer to 1. d4, I had to ask myself things that I liked about certain opening and things I didn't like. For example, when playing against the London System I prefer having a pawn on d5 to fight for the e4 square. Personally, I would rather play the IQP vs. passive LSB because (especially at low levels) the sort of opponent I'm likely to face is unlikely to be able to make much of the structural deficiencies in my position.
I had to discard a great many openings due lack time to devote to memorization (Grunfeld, KID, Semi-Slav etc.). I settled on the Tarrasch Defense. Active pieces (good for tactics) but leaves you with an IQP in many lines. Side note : I am currently making my way through 'Meeting 1. d4' by Aagard. I have only started but I like what I see so far.

user109: Besides what Andrew had mentioned, I would also recommend looking into:
Von Henning Schara Gambit
Tarrasch Defense


user12: TL;DR
Good repertoire for fighting chess for white.  As black, you can play 1...c5 against 1.Nf3, and against 1.d4 I would recommend looking at the following openings and picking your favorite:  

Grunfeld
King's Indian Defense
Slav
Dutch


This is going to be a long answer, so bear with me...
Your white opening looks acceptable.  I won't really get into the merits of any of your specific choices other than to say be careful with the Advance Caro and Advance French - those don't always let you play a tactical game against strong opposition.  You could look into the French Tarrasch (surprising, I know, but even the closed main line gives white kingside attacking chances) and the Panov-Botvinnik Attack against the Caro.
Against 1.d4, almost all players have difficulty right now.  From the very best GM's down to the average club players, the last 5-10 years have shown that white has excellent chances for an advantage with queen pawn openings.  There are two openings that are currently "in vogue" at the top level - the Grunfeld and the Slav.  These two openings are by no means the only options, but current theory holds that black can maintain equality with best play, and additionally, black has chances to win with both openings.  I'll also mention the Dutch, the King's Indian Defense, the Nimzo/QID, and the classical QGD in this answer.
Grunfeld
The Grunfeld is one of the best openings for black against 1.d4 right now.  Black does not occupy the center, but instead attacks it from afar with moves like Bg7, c5, Nc6, and sometimes e5 and Rd8.  White has not been able to find a clear advantage against black's best play, and most Grunfeld endgames favor black due to the queenside pawn structure.  I would recommend the Grunfeld for players who are not afraid to study theory - sometimes a LOT of theory.  Furthermore, Grunfeld players should be willing to take on certain disadvantages in exchange for counterplay.  Black will frequently have a large space disadvantage early in the game and it takes experience to push back white to get to an advantageous endgame.  That said, the Grunfeld offers EXCELLENT winning chances against lower rated players, especially in endgames that look equal at first.
Slav
The Slav is another very common opening right now.  If you want a crash course on the Slav, you can look at Anand's games in the last few matches that he has played.  The Slav is another opening that can require a lot of theory, especially when you get into the Botvinnik System and the Moscow/Anti-Moscow variations.  The biggest drawback to the Slav is that white can force a symmetrical game by playing an early cxd5.  The Exchange Slav is very boring, but if you are a higher rated player, it is still possible to grind your way to victory in the Exchange Slav.  
Dutch
The Dutch is quite possibly the best opening for a tactical game, but black is really playing with fire.  It is very easy to slip into a lost position if you are not playing every move accurately.  Within the Dutch, there are a few systems that are all playable - the Stonewall, the Leningrad, and the Classical.  The biggest advantage to playing the Dutch is that white players that have memorized 25 moves in the Catalan won't be able to play by memory and will have to figure out what to do at the board.  Furthermore, black frequently will get a kingside attack going with the Leningrad Dutch.  
King's Indian Defense
The KID is another opening where black can be positionally lost without many mistakes.  For example, if you play the Queen's Gambit Declined as black, you can make 3 or 4 subpar moves without really getting a bad position.  The Dutch and the KID are another story - one misstep and black might already be losing.  If you are willing to take that chance, or you are confident in your ability to deal with tactics, then the KID is a good choice.  It offers black a kingside attack (usually) and chances for the full point.  
Other Openings
Just to touch on alternatives - the QGD is always a solid choice, but black can have a very hard time finishing development.  The bishop on c8 sometimes cannot be developed until move 20 or even later.  If you are not comfortable playing a cramped position, stay away from the QGD.
The Indian Systems (Nimzo and QID) are good choices, but per your question, I didn't mention them very much.  At the GM level, these defenses are still played, but white has found ways to get a good game against both the Nimzo (look into 4.Qc2) and the QID.  Furthermore, since the Catalan is so popular, you will frequently not get the chance to play a true Indian Defense.
Final Thoughts
You might notice that I did not recommend any gambits like the Albin Countergambit or the Budapest.  With good play, white gets a great position against both of those choices.  With quiet play, white still gets an equal position and black's initiative dries up quite quickly (for example g3 against the Budapest).  Additionally, the Benoni and the Benko Gambit are not mentioned because black has to solve quite a few problems according to modern theory.  
Ultimately, you will have to try out all of these openings and decide which one you like the best.  Personally, I play the KID, the Grunfeld, and the Dutch mostly.  The main point is that if you want a super sharp game, don't allow symmetrical positions (for example, your choice to play the Sicilian as black against 1.e4).  

279: <p>I'm preparing an opening repertoire for a small "open tournament" that will take place in a few weeks.</p>

<p>I think I'm quite decent at tactical play, and I like situations that give me the initiative - that is, attacking; or counterattacking when my opponent is attacking, since I can't stand rocky but passive defense. I also like games in which I can concentrate my attacks against specific targets (isolated pawn, opponent's blocked center, etc.).</p>

<p>So far, my repertoire is built this way:</p>

<p><strong>with White</strong>: basically <code>1.e4</code></p>

<ul>
<li>against <code>1...e5</code>, Italian (all variations) and 2-Knights (all variations), 4-Knights (all variations), and some variations of the Russian. Perhaps I'll add some variations of the Scotch Game;</li>
<li>for <code>1...c5</code> I've studied some of the main lines of the Open Sicilian, the Alapin and the Closed Sicilian;</li>
<li>for <code>1...c6</code> (Caro-Kann) I have prepared the Advance Variation and some of the main lines;</li>
<li>against <code>1...e6</code> (French) I know the lines of the Advance Variation;</li>
</ul>

<p>Against other defenses, I've simply studied the strategical ideas behind the most famous "lesser" defences (Scandinavian, Pirc, Nimzowitsch, etc.), and I plan to play natural moves without searching for "early confutation".</p>

<p><strong>with Black</strong>:</p>

<ul>
<li>against <code>1.e4</code> I think I know kinda well Sicilian Kan, Paulsen and Sveshnikov, and many variations of the French Defense;</li>
<li>against <code>1.c4</code> I usually play the Reverse-Sicilian, and sometimes the Symmetrical English.</li>
</ul>

<p>But I cannot find a decent opening to play against <code>1.d4</code> (just a lesser opening, indeed xD). And this can be a problem also against <code>1.Nf3</code>, due to the many transpositions.</p>

<p>I used to play the "Nimzo-Indian + Queen's Indian" pair, but recently I found that those openings do not suit my playing style, especially the Queen's Indian. I've looked something about the Slav Defense, but I'm really scared of the many transposition into Semi-Slav and Queen's Gambit Declined (and the study that lies behind!). And I'm even more scared of theory speaking of King's Indian and Gruenfeld.</p>

<p>So, does anyone know defenses that may suit my playing style with Black against <code>1.d4</code>? Do you think that, if I fill this void, my repertoire is complete enough?</p>
 18809: <p>Because tactical complications often come with very sharp positions, a tactical opening often means a lot of theory. So, it would depend on your skill level and, more importantly, on how many hours you want to spend building your repertoire.</p>

<p>At a lower skill level, <code>1.e4</code> looks like a nice choice, but in fact it's not the only one! There is <code>1.f4</code>, the King's indian attack, or maybe some <code>d4, Nc3, Bg5, Qd3/d2, 0-0-0, e4</code> system that also allow for complicated tactical games and may not need such a deep study.</p>

<p>With Black you can try the Tarrasch Defence against <code>1.d4</code> (central isolated pawns will suit you perfectly) and <code>1...e5</code> against <code>1.e4</code></p>

<p>If you are a strong player and you can dedicate a long time to studying openings, I would definitely stick to <code>1.e4</code>as White, playing the Open Sicilian, the Scotish Opening, the Panov Attack and probably <code>3.Nd2</code>against the French (or even <code>3. exd5 exd5 4.c4</code>)</p>

<p>When playing Black, the Sicilian Dragon appears to be the best choice to me (Najdorf or Taimanov are good alternatives). I'd choose the Grunfeld Defence against <code>1.e4</code>. Knowing the main ideas in the Dutch Defence and the Closed Sicilian is also helpful when playing against <code>1.c4</code>and <code>1.Nf3</code>.</p>

<p>Finally, I would remark that we should distinguish "tactical player" from "attacking player". For instance, the King's Indian and the Closed Sicilian are great choices for an attacking player, but the attack often comes as a result of a deep comprehension of strategical principles, rather than just "brute force". That's what led me to suggesting the Dragon Sicilan rather than other lines like the Scheveningen.</p>
 10233: <p>Nimzo-Indian Defense hands down. Black scores well, it's aggressive in nature and gives you targets as Black to attack. I would not touch the Dutch, Benoni, King's Indian or the Slav with a 10-foot pole. Slow grinding games is not what you want.</p>

<p>Go All in with the Nimzo!</p>
 1733: <p>Usually if i'm playing black and and my opponent plays the Queens Gambit I'll attempt to play the Benko Gambit, a very aggressive opening. If that does not work I transpose into the Pirc. It's hard to fall into traps and things like that in the opening, which gives you a good middle game and to play chess.</p>
 1312: <p>The opening you should be considering is the <strong>Benoni Defence</strong>. All decent lines by white lead to highly tactical middlegames where both sides are constantly making short-term threats. For this reason it has been a favorite for attacking and tactical players who wanted to play for middlegame wins as black, for example: Mikhail Tal, Bobby Fischer, Veselin Topalov, and Vugar Gashimov.</p>

<p>Another good option to consider is the <strong>Benko Gambit</strong>; although perfect play by white probably wins, below the grandmaster level the active piece play it gives black should allow you take advantage of your preference for active middlegames.</p>

<p>I play the Grunfeld, but based on your description I might caution you against it. Playing the Grunfeld correctly requires extensive book knowledge, which for me has added up to memorization. Also can be difficult to book up on the Grunfeld, because you usually want to play the same moves regardless of what white does, but choosing the correct <em>move order</em> is critical. If your opponent is deeply booked as white against the Grunfeld, and most expert level 1. d4 players and up will be, is very easy as black to play moves out of order and wind up with a stable but uncomfortable middlegame position where you are just worse.</p>

<p>However, if lots of book study doesn't sound scary, then the Grunfeld is an excellent choice: you will regularly get equal but dynamic middlegames as black.</p>

<p>You didn't include your ELO so I'll throw this out: against 1. d4 there is an offbeat line that can be effective at the class level, which is the <strong>Budapest gambit</strong> (1. d4 Nf6 2. c4 e5?!). Strictly speaking it is almost definitely unsound, but it is a strict upgrade over the Englund (which is unplayable, frankly).</p>
 4543: <p>The Chigorin is a good opening for tactical players. As in the Sveshnikov the pawn structure is half fixed half dynamic if you know what I mean. Play 1...Nc6 by C. Wisneweski is the best book in my opinion. At some stage if you keep improving you will need a line against the Pirc as good players in open tournaments tend to know it quite well.</p>
 7450: <p>When choosing a black opening you have to come to grips with the thought that black (usually) has to make some concession <em>in any chosen opening</em>. </p>

<p>When looking for my answer to <code>1. d4</code>, I had to ask myself things that I liked about certain opening and things I didn't like. For example, when playing against the <code>London System</code> I prefer having a pawn on <code>d5</code> to fight for the <code>e4</code> square. Personally, I would rather play the IQP vs. passive LSB because (especially at low levels) the sort of opponent I'm likely to face is unlikely to be able to make much of the structural deficiencies in my position.</p>

<p>I had to discard a great many openings due lack time to devote to memorization (Grunfeld, KID, Semi-Slav etc.). I settled on the <code>Tarrasch Defense</code>. Active pieces (good for tactics) but leaves you with an IQP in many lines. Side note : I am currently making my way through 'Meeting 1. d4' by Aagard. I have only started but I like what I see so far.</p>
 109: <p>Besides what Andrew had mentioned, I would also recommend looking into:</p>

<pre><code>Von Henning Schara Gambit
Tarrasch Defense
</code></pre>
 12: <h2>TL;DR</h2>

<p>Good repertoire for fighting chess for white.  As black, you can play <code>1...c5</code> against <code>1.Nf3</code>, and against <code>1.d4</code> I would recommend looking at the following openings and picking your favorite:  </p>

<ul>
<li>Grunfeld</li>
<li>King's Indian Defense</li>
<li>Slav</li>
<li>Dutch</li>
</ul>

<hr>

<p>This is going to be a long answer, so bear with me...</p>

<p>Your white opening looks acceptable.  I won't really get into the merits of any of your specific choices other than to say be careful with the Advance Caro and Advance French - those don't always let you play a tactical game against strong opposition.  You could look into the French Tarrasch (surprising, I know, but even the closed main line gives white kingside attacking chances) and the Panov-Botvinnik Attack against the Caro.</p>

<p>Against <code>1.d4</code>, almost all players have difficulty right now.  From the very best GM's down to the average club players, the last 5-10 years have shown that white has excellent chances for an advantage with queen pawn openings.  There are two openings that are currently "in vogue" at the top level - the Grunfeld and the Slav.  These two openings are by no means the only options, but current theory holds that black can maintain equality with best play, and additionally, black has chances to win with both openings.  I'll also mention the Dutch, the King's Indian Defense, the Nimzo/QID, and the classical QGD in this answer.</p>

<h2>Grunfeld</h2>

<p>The Grunfeld is one of the best openings for black against <code>1.d4</code> right now.  Black does not occupy the center, but instead attacks it from afar with moves like Bg7, c5, Nc6, and sometimes e5 and Rd8.  White has not been able to find a clear advantage against black's best play, and most Grunfeld endgames favor black due to the queenside pawn structure.  I would recommend the Grunfeld for players who are not afraid to study theory - sometimes a LOT of theory.  Furthermore, Grunfeld players should be willing to take on certain disadvantages in exchange for counterplay.  Black will frequently have a large space disadvantage early in the game and it takes experience to push back white to get to an advantageous endgame.  That said, the Grunfeld offers EXCELLENT winning chances against lower rated players, especially in endgames that look equal at first.</p>

<h2>Slav</h2>

<p>The Slav is another very common opening right now.  If you want a crash course on the Slav, you can look at Anand's games in the last few matches that he has played.  The Slav is another opening that can require a lot of theory, especially when you get into the Botvinnik System and the Moscow/Anti-Moscow variations.  The biggest drawback to the Slav is that white can force a symmetrical game by playing an early cxd5.  The Exchange Slav is very boring, but if you are a higher rated player, it is still possible to grind your way to victory in the Exchange Slav.  </p>

<h2>Dutch</h2>

<p>The Dutch is quite possibly the best opening for a tactical game, but black is really playing with fire.  It is very easy to slip into a lost position if you are not playing every move accurately.  Within the Dutch, there are a few systems that are all playable - the Stonewall, the Leningrad, and the Classical.  The biggest advantage to playing the Dutch is that white players that have memorized 25 moves in the Catalan won't be able to play by memory and will have to figure out what to do at the board.  Furthermore, black frequently will get a kingside attack going with the Leningrad Dutch.  </p>

<h2>King's Indian Defense</h2>

<p>The KID is another opening where black can be positionally lost without many mistakes.  For example, if you play the Queen's Gambit Declined as black, you can make 3 or 4 subpar moves without really getting a bad position.  The Dutch and the KID are another story - one misstep and black might already be losing.  If you are willing to take that chance, or you are confident in your ability to deal with tactics, then the KID is a good choice.  It offers black a kingside attack (usually) and chances for the full point.  </p>

<h2>Other Openings</h2>

<p>Just to touch on alternatives - the <strong>QGD</strong> is always a solid choice, but black can have a very hard time finishing development.  The bishop on c8 sometimes cannot be developed until move 20 or even later.  If you are not comfortable playing a cramped position, stay away from the QGD.</p>

<p>The <strong>Indian Systems</strong> (Nimzo and QID) are good choices, but per your question, I didn't mention them very much.  At the GM level, these defenses are still played, but white has found ways to get a good game against both the Nimzo (look into <code>4.Qc2</code>) and the QID.  Furthermore, since the Catalan is so popular, you will frequently not get the chance to play a true Indian Defense.</p>

<h2>Final Thoughts</h2>

<p>You might notice that I did not recommend any gambits like the Albin Countergambit or the Budapest.  With good play, white gets a great position against both of those choices.  With quiet play, white still gets an equal position and black's initiative dries up quite quickly (for example g3 against the Budapest).  Additionally, the Benoni and the Benko Gambit are not mentioned because black has to solve quite a few problems according to modern theory.  </p>

<p>Ultimately, you will have to try out all of these openings and decide which one you like the best.  Personally, I play the KID, the Grunfeld, and the Dutch mostly.  The main point is that if you want a super sharp game, don't allow symmetrical positions (for example, your choice to play the Sicilian as black against <code>1.e4</code>).  </p>
