I've thought about making a Tales from the Loop "retroclone", then applying it to some other setting. Candidates include something like the Hilda series of children's books (sort of kid-friendly Vaesen), adult ghost hunters (also Vaesen-ish but without threats to life and limb), and one where players are immortal "elves" (essentially vaesen) who suffer psychic and social losses but no permanent physical consequences.
Most of the work would be cutting things out, then adding rules for Conditions and whatever the (eventual) setting would need. Attributes and skills might also need renaming, depending on the setting. I do worry, though, that if I have to cut and/or rewrite too much I'm better off building from scratch.
HILDA: This isn't much of a pep talk. Can't you say, 'you can do it!'
ALFUR: Sure! You can do it! (Statement for encouragement purposes only. You may not actually be able to do it.)
-- Hilda ep. 9 (Netflix, 2018)