The only tool I usually use is the chessboard in my head, which usually
limits my games to things that I can playtest blindfold.
Given a chessboard and a few coins and a pencil and paper, one can do a
wider range of games than can be done using just the mental board; but then
I wonder if that distracts one from the 'pure thought' which proves so
productive.
I would have to say that whatever works well for you is best.