[l-lousy]

A gardening simulator game with Sam as the main character

Mirrors edge, but with gollum

I think you could make a really good Witcher style show/movie/game with Aragorn’s backstory

[WJW]

Dwarf fortress but (even) more explicitly Tolkien-themed.

[suprjami]

Already exists: https://github.com/sil-quirk/sil-q

[haasted]

Animal Crossing in the Shire.

[soco]

Forest tending simulator, with ents. They could also fight those pesky dwarves - crossover with their fortress game.