Krypt, Ravensburger, 631 (+1?) pieces. Never had an extra piece before! Finished in one sitting. : r/Jigsawpuzzles
Amazon.com: Ravensburger Krypt Silver 654 Piece Blank Jigsaw Puzzle Challenge for Adults – Every Piece is Unique, Softclick Technology Means Pieces Fit Together Perfectly : Varios: Everything Else