MINOR PIECES - the interplay between Bishops and Knights (trying to make one superior to the other)
PAWN STRUCTURE - a broad subject that encompasses doubled pawns, isolated pawns, backward pawns, passed pawns, etc
SPACE - the annexation of territory on a chess board
MATERIAL - owning pieces of greater value than the opponent's
FILES AND SQUARES - files, ranks, and diagonals act as pathways for your pieces, while squares act as homes. Whole plans can center around the domination of a file, or the creation of a weak square in the enemy camp
DEVELOPMENT - a lead in development gives you more force in a specific area of the board. This is a temporary imbalance because the opponent will eventually catch up.
INITIATIVE - dictating the tempo of a game. This is also a temporary imbalance.