Grant Acedrex

Grant Acedrex is a medieval chess variant played on a 12x12 board, using pieces called king, aanca, rhinoceros, rook, lion, crocodile, giraffe, and pawn. Many of these pieces move like pieces in modern chess, but for example the giraffe moves one step forward and then two steps diagonally. A variant used dice to determine which pieces could be moved next.

Wikipedia hast a wonderful list of chess variants, including Hexagonal Chess, Infinite Chess, and "Racing Kings".