... are games with random positions similar to FRC or Corner Chess.A very interesting wild variant is "Style 3" at USCL:
" In this variant the set of pieces is randomly chosen (subject to the constraint that there is one king of each color).It is quite possible to get more than the normal number of a given piece, such as three rooks or two queens. The pieces are
placed on the first rank behind the pawns, the position of Black's pieces mirrors White's placement, and castling is not allowed."
Three game examples played by me with a time of three minutes each player for the whole game: