user11609: I deal with this problem every time. I have some 'default' repertoire and when preparing against concrete opponent, I find that it is highly probable we will reach some concrete well known position and I want be the one to come with system he can't expect me to play. Ok I can use book, engine, games to create interesting system myself, but it takes soooo much time. People already made thousands of preparations like this, coming with a sharp forcing idea hard to refute over the board, playing new move with completely different approach compared to main lines... Is there somewhere something like market of these ideas? Just pgn with 20 lines, for example. Or text. Anything that is good for titled players, computer checked lines, dangerous surprises for one game etc.

user14202: The SOS ("Secrets of Opening Surprises") books and articles (in New in Chess magazine) can be good references.  Once in the USATW I was paired up against a 2450 rated player.  I found references with a quick online search that he played the Caro-Khan.  I walked in the bookstore and looked in an SOS book and found a line Kasparov used in blitz a lot.  After 10 minutes of preparation I was armed  to get my well booked opponent out of his element and I won my best game of the tournament.
I've done such things with the Chess Informants a lot including preparation against Yermolinsky in the US Open.  I would say Chess Informant is best if you have the time and money.

11609: <p>I deal with this problem every time. I have some 'default' repertoire and when preparing against concrete opponent, I find that it is highly probable we will reach some concrete well known position and I want be the one to come with system he can't expect me to play. Ok I can use book, engine, games to create interesting system myself, but it takes soooo much time. People already made thousands of preparations like this, coming with a sharp forcing idea hard to refute over the board, playing new move with completely different approach compared to main lines... Is there somewhere something like market of these ideas? Just pgn with 20 lines, for example. Or text. Anything that is good for titled players, computer checked lines, dangerous surprises for one game etc.</p>
 14202: <p>The SOS ("Secrets of Opening Surprises") books and articles (in New in Chess magazine) can be good references.  Once in the USATW I was paired up against a 2450 rated player.  I found references with a quick online search that he played the Caro-Khan.  I walked in the bookstore and looked in an SOS book and found a line Kasparov used in blitz a lot.  After 10 minutes of preparation I was armed  to get my well booked opponent out of his element and I won my best game of the tournament.
I've done such things with the Chess Informants a lot including preparation against Yermolinsky in the US Open.  I would say Chess Informant is best if you have the time and money.</p>
