Inspiration Problem that was posed here. It can be restated as "Within a n x n chessboard, what is the maximum number of rooks that can be placed on the board, where each rook has a path off the board?" Similar statements can be constructed for the knight, bishop, and queen.
Classical Chess Packing - The original repo, this relates to the original problem statement found above. Stalemate Chess Packing - The maximum number of pieces of type X, such that the opponent's king will be in stalemate.