Team-mate chess is a variant with many different unusual pieces.

The idea behind team-mate chess was to have a variant where no single piece would be able (with the help of its own king) to force checkmate onto a bare king, but where you would always need at least a pair of pieces (a 'team') to do that. So that all basic checkmates become similar to the bishop + knight checkmate of orthodox Chess. To get as many such different end-games as possible, all pieces in the initial setup are different. Furthermore, a piece type not present initially can be obtained through promotion.

Team-mate chess was conceived in 2014 by H.G.Muller.