Chess author Jeremy Silman, who champions the "imbalance" idea, gives a list:
- Minor pieces (bishops vs knights)
- Pawn structure
- Space
- Material
- Files and squares
- Development
- Initiative
I would add how much time is left on the clock, though that is not a feature of the board.
An example: say you have a bishop and your opponent has a knight. This is an imbalance, and you want to exploit it by making your bishop better than their knight. Concretely that means trading pawns, to open up the game, so your bishop can bring its long-range strengths to bear.
