The Cutting Room Floor is a wiki-like website which claims to recopilate "unused and cut content from video games. From debug menus, to unused music, graphics, enemies, or levels, many games have content never meant to be seen by anybody but the developers — or even meant for everybody, but cut due to time/budget constraints".
It has a section for Lemmings series' ports, check it out here:
https://tcrf.net/Category:Lemmings_series
I know I'm not very smart. So come to ask for knowledge from all of you.