It would be great to add the chess variant Pre-Chess. The game begins with white and black having just their second rank full of pawns, each player starting with white places one of their pieces on their back rank, and once all pieces are placed, play begins. The only limitation on piece placement is that bishops must be on opposite colored squares. If king and rook are placed on traditional squares, castling is possible, otherwise it is not allowed.
This variant retains all the benefits of chess960 (eliminating opening theory), while removing the drawbacks, the randomness of starting position, and sometimes unfair starting position. Since the players are responsible for deploying their forces as they wish, they are strategically engaged from the beginning. You can either place your pieces in a formation you like, or try to respond to the choices of your opponent and find the optimum reply.