Lemmings / Psygnosis
Psygnosis only published Lemmings, it was not an in-house project.
Same with most of the decent stuff they released - unfortunately they purchased lots of Silicon Graphics workstations early on and so were fixated with justifying that purchase by churning out lots of FMV / pre-rendered games, which were universally awful and often got canned or had very limited releases.
It wasn't until they were bought out by Sony and so got involved in PSX dev that they started to work on modern realtime 3D games such as Wipeout.
Carmageddon was pitched as a proposed internal project for the Camden studio, but management turned it down. Thankfully Adrian Curry then quit and took the idea elsewhere.