I can't find an official source, but from the comments, apparently Little Nightmares
offered 2 DLC masks (Scarecrow Sack and Upside-down Teapot), a wallpaper and the soundtrack.
Except for the wallpaper, they are all included in the new DLCs of the game.
Also, maybe you haven't seen the edit of my previous post with Dungeons 3
and Legend of Heroes
Edit: New entries! BATTLETECH
"Pre-Order today to receive the BATTLETECH - Shadowhawk Pack which includes an alternate skin for the formidable Shadowhawk 'Mech plus an exclusive wallpaper, to be delivered at launch." FTL: Advanced Edition
"Buy Into the Breach until March 6th and get FTL: Advanced Edition for FREE!"
Great! Too many to keep track :) Been a busy week this week :) Was about to come in to update about Into The Breach and saw all the messages lol