user-1: I don't like the mouse and want to use the keyboard as much as possible.
SCID vs PC has a webpage with keyboard shortcuts, but the same does not seem to exist for SCID.
This answer to "How to flip the board" discloses the . shortcut,
which I found documented in Help > Contents > The Scid main window, however only a few
of them are to be found in that section. Some are spread out in the Help, others might be missing.
Where can I find a list of all SCID shortcuts?

user-1: After greping the source code, I found them in /usr/share/scid/tcl/keyboard.tcl
in GNU/Linux (if someone knows the path for other OS please share it).
Also, a comment in that file says
> By editing this file you can customize the keyboard shortcuts,
in order to best suit your preferences.
It is not necessary to recompile scid after changing this file.

For convenience, I have extracted all the bindings and their corresponding actions below
(this is not proper TCL syntax, it is just for reading convenience).
<Left>                Back
<Right>               Forward
<Up>                  Back 10 moves
<Down>                Forward 10 moves
<Home>                Exit Variation/Go to game start
<End>                 Go to game end
<Alt-F4>              Exit
<Control-o>           Open a database
<Control-w>           Close the current database
<Control-z>           undo
<Control-y>           redo
<Control-n>           new game
<Control-s>           save game
<Control-S>           save as new game
<F11>                 toggle fullscreen
<period>              flip/rotate board
<s>                   ::setupBoard
<KeyPress-v>          show variations dialog
<Control-Key-$i>      Change current database
<F6>                  ::book::open
<F12>                 ::CorrespondenceChess::CCWindow
<Control-F12>         ::CorrespondenceChess::OpenCorrespondenceDB; ::CorrespondenceChess::ReadInboxg
<Alt-F12>             ::CorrespondenceChess::OpenCorrespondenceDB; ::CorrespondenceChess::FetchGamesg
<Control-equal>       ::tb::Open
<Control-d>           ::windows::switcher::Open
<Control-e>           makeCommentWin
<Control-i>           ::windows::stats::Open
<Control-l>           ::windows::gamelist::Open
<Control-m>           ::maint::OpenClose
<Control-p>           ::pgn::OpenClose
<Control-t>           ::tree::make
<Control-E>           ::windows::eco::OpenClose
<Control-K>           ::ptrack::make
<Control-O>           ::optable::makeReportWin
<Control-P>           ::plist::toggle
<Control-T>           ::tourney::toggle
<Control-X>           crosstabWin
<F2>                  "::makeAnalysisWin 1 0"
<F3>                  "::makeAnalysisWin 2 0"
<F4>                  .analysisWin1.b1.bStartStop invoke g
<F5>                  .analysisWin2.b1.bStartStop invoke g
<Control-A>           makeAnalysisWin
<Control-Shift-2>     "makeAnalysisWin 2"
<Control-a>           sc_var create; updateBoard -pgng
<Control-B>           ::search::board
<Control-H>           ::search::header
<Control-M>           ::search::material
<Control-KeyPress-U>  ::search:::usefile
<Control-C>           ::copyFEN
<Control-V>           ::pasteFEN
<Control-E>           ::tools::email
<Control-I>           importPgnGame
<Control-D>           sc_move ply [sc_eco game ply]; updateBoardg
<Control-G>           tools::graphs::filter::Open
<Control-J>           tools::graphs::absfilter::Open
<Control-u>           ::game::GotoMoveNumber
<Control-Y>           findNovelty
<F1>                  helpWindow Contentsg
<Control-N>           nameEditor
<Control-slash>       ::file::finder::Open
<Control-Shift-Up>    ::game::LoadNextPrev firstg
<Control-Shift-Down>  ::game::LoadNextPrev lastg
<Control-Up>          ::game::LoadNextPrev previousg
<Control-Down>        ::game::LoadNextPrev nextg
<Control-question>    ::game::LoadRandom
<minus><minus>        addMove null null

<exclam><Return>             "sc_pos addNag !; updateBoard -pgn"
<exclam><exclam><Return>     "sc_pos addNag !!; updateBoard -pgn"
<exclam><question><Return>   "sc_pos addNag !?; updateBoard -pgn"
<question><Return>           "sc_pos addNag ?; updateBoard -pgn"
<question><question><Return> "sc_pos addNag ??; updateBoard -pgn"
<question><exclam><Return>   "sc_pos addNag ?!; updateBoard -pgn"
<plus><minus>                "sc_pos addNag +-; updateBoard -pgn"
<plus><slash>                "sc_pos addNag +/-; updateBoard -pgn"
<plus><equal>                "sc_pos addNag +=; updateBoard -pgn"
<equal><Return>              "sc_pos addNag =; updateBoard -pgn"
<minus><plus>                "sc_pos addNag -+; updateBoard -pgn"
<minus><slash>               "sc_pos addNag -/+; updateBoard -pgn"
<equal><plus>                "sc_pos addNag =+; updateBoard -pgn"
<asciitilde><Return>         "sc_pos addNag ~; updateBoard -pgn"
<asciitilde><equal><Return>  "sc_pos addNag ~=; updateBoard -pgn"


-1: <p>I don't like the mouse and want to use the keyboard as much as possible.
SCID vs PC has a <a href="http://scidvspc.sourceforge.net/doc/ShortCuts.htm" rel="nofollow noreferrer">webpage with keyboard shortcuts</a>, but the same does not seem to exist for SCID.
<a href="https://chess.stackexchange.com/a/16782">This answer to &quot;How to flip the board&quot;</a> discloses the <kbd>.</kbd> shortcut,
which I found documented in <code>Help &gt; Contents &gt; The Scid main window</code>, however only a few
of them are to be found in that section. Some are spread out in the Help, others might be missing.
Where can I find a list of all SCID shortcuts?</p>
 -1: <p>After <code>grep</code>ing the source code, I found them in <code>/usr/share/scid/tcl/keyboard.tcl</code>
in GNU/Linux (if someone knows the path for other OS please share it).</p>
<p>Also, a comment in that file says</p>
<pre><code>&gt; By editing this file you can customize the keyboard shortcuts,
in order to best suit your preferences.
It is not necessary to recompile scid after changing this file.
</code></pre>
<p>For convenience, I have extracted all the bindings and their corresponding actions below
(this is <strong>not</strong> proper TCL syntax, it is just for reading convenience).</p>
<pre><code>&lt;Left&gt;                Back
&lt;Right&gt;               Forward
&lt;Up&gt;                  Back 10 moves
&lt;Down&gt;                Forward 10 moves
&lt;Home&gt;                Exit Variation/Go to game start
&lt;End&gt;                 Go to game end
&lt;Alt-F4&gt;              Exit
&lt;Control-o&gt;           Open a database
&lt;Control-w&gt;           Close the current database
&lt;Control-z&gt;           undo
&lt;Control-y&gt;           redo
&lt;Control-n&gt;           new game
&lt;Control-s&gt;           save game
&lt;Control-S&gt;           save as new game
&lt;F11&gt;                 toggle fullscreen
&lt;period&gt;              flip/rotate board
&lt;s&gt;                   ::setupBoard
&lt;KeyPress-v&gt;          show variations dialog
&lt;Control-Key-$i&gt;      Change current database
&lt;F6&gt;                  ::book::open
&lt;F12&gt;                 ::CorrespondenceChess::CCWindow
&lt;Control-F12&gt;         ::CorrespondenceChess::OpenCorrespondenceDB; ::CorrespondenceChess::ReadInboxg
&lt;Alt-F12&gt;             ::CorrespondenceChess::OpenCorrespondenceDB; ::CorrespondenceChess::FetchGamesg
&lt;Control-equal&gt;       ::tb::Open
&lt;Control-d&gt;           ::windows::switcher::Open
&lt;Control-e&gt;           makeCommentWin
&lt;Control-i&gt;           ::windows::stats::Open
&lt;Control-l&gt;           ::windows::gamelist::Open
&lt;Control-m&gt;           ::maint::OpenClose
&lt;Control-p&gt;           ::pgn::OpenClose
&lt;Control-t&gt;           ::tree::make
&lt;Control-E&gt;           ::windows::eco::OpenClose
&lt;Control-K&gt;           ::ptrack::make
&lt;Control-O&gt;           ::optable::makeReportWin
&lt;Control-P&gt;           ::plist::toggle
&lt;Control-T&gt;           ::tourney::toggle
&lt;Control-X&gt;           crosstabWin
&lt;F2&gt;                  &quot;::makeAnalysisWin 1 0&quot;
&lt;F3&gt;                  &quot;::makeAnalysisWin 2 0&quot;
&lt;F4&gt;                  .analysisWin1.b1.bStartStop invoke g
&lt;F5&gt;                  .analysisWin2.b1.bStartStop invoke g
&lt;Control-A&gt;           makeAnalysisWin
&lt;Control-Shift-2&gt;     &quot;makeAnalysisWin 2&quot;
&lt;Control-a&gt;           sc_var create; updateBoard -pgng
&lt;Control-B&gt;           ::search::board
&lt;Control-H&gt;           ::search::header
&lt;Control-M&gt;           ::search::material
&lt;Control-KeyPress-U&gt;  ::search:::usefile
&lt;Control-C&gt;           ::copyFEN
&lt;Control-V&gt;           ::pasteFEN
&lt;Control-E&gt;           ::tools::email
&lt;Control-I&gt;           importPgnGame
&lt;Control-D&gt;           sc_move ply [sc_eco game ply]; updateBoardg
&lt;Control-G&gt;           tools::graphs::filter::Open
&lt;Control-J&gt;           tools::graphs::absfilter::Open
&lt;Control-u&gt;           ::game::GotoMoveNumber
&lt;Control-Y&gt;           findNovelty
&lt;F1&gt;                  helpWindow Contentsg
&lt;Control-N&gt;           nameEditor
&lt;Control-slash&gt;       ::file::finder::Open
&lt;Control-Shift-Up&gt;    ::game::LoadNextPrev firstg
&lt;Control-Shift-Down&gt;  ::game::LoadNextPrev lastg
&lt;Control-Up&gt;          ::game::LoadNextPrev previousg
&lt;Control-Down&gt;        ::game::LoadNextPrev nextg
&lt;Control-question&gt;    ::game::LoadRandom
&lt;minus&gt;&lt;minus&gt;        addMove null null

&lt;exclam&gt;&lt;Return&gt;             &quot;sc_pos addNag !; updateBoard -pgn&quot;
&lt;exclam&gt;&lt;exclam&gt;&lt;Return&gt;     &quot;sc_pos addNag !!; updateBoard -pgn&quot;
&lt;exclam&gt;&lt;question&gt;&lt;Return&gt;   &quot;sc_pos addNag !?; updateBoard -pgn&quot;
&lt;question&gt;&lt;Return&gt;           &quot;sc_pos addNag ?; updateBoard -pgn&quot;
&lt;question&gt;&lt;question&gt;&lt;Return&gt; &quot;sc_pos addNag ??; updateBoard -pgn&quot;
&lt;question&gt;&lt;exclam&gt;&lt;Return&gt;   &quot;sc_pos addNag ?!; updateBoard -pgn&quot;
&lt;plus&gt;&lt;minus&gt;                &quot;sc_pos addNag +-; updateBoard -pgn&quot;
&lt;plus&gt;&lt;slash&gt;                &quot;sc_pos addNag +/-; updateBoard -pgn&quot;
&lt;plus&gt;&lt;equal&gt;                &quot;sc_pos addNag +=; updateBoard -pgn&quot;
&lt;equal&gt;&lt;Return&gt;              &quot;sc_pos addNag =; updateBoard -pgn&quot;
&lt;minus&gt;&lt;plus&gt;                &quot;sc_pos addNag -+; updateBoard -pgn&quot;
&lt;minus&gt;&lt;slash&gt;               &quot;sc_pos addNag -/+; updateBoard -pgn&quot;
&lt;equal&gt;&lt;plus&gt;                &quot;sc_pos addNag =+; updateBoard -pgn&quot;
&lt;asciitilde&gt;&lt;Return&gt;         &quot;sc_pos addNag ~; updateBoard -pgn&quot;
&lt;asciitilde&gt;&lt;equal&gt;&lt;Return&gt;  &quot;sc_pos addNag ~=; updateBoard -pgn&quot;
</code></pre>
