The Crazyhouse piece: Moves as knight. Can be places on any open square on the board.
The 3-Check piece: If you get checked 3 times by this piece, you lose. Moves as a queen.
The KOTH piece: Moves as king. Behaves like king. If you get it on the center squares, you win. If it is checkmated, you lose. (this means there are 2 kings on the board now)
The 960 piece: A random piece. You can choose to start with normal set-up or have the 960 piece occupy a random spot in your set-up.
The Sneaky: is invisible to the opponent but the annotation is still visible so you have to pay attention. Moves like a king.