If you are looking for just one seat cover piece, check with salvage yards. Had a friend who had an actual hole about an inch across burned into his BMW 320i seat, and half an inch deep (ember from a campfire on a camping trip that blew in his open window when parked). BMW wanted over $1K for a new seat-bottom, foam and cover. He found a wrecker with one - cost him $100.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE