What games have what you’d call really good worldbuilding, and what in particular do you like about them?
https://en.wikipedia.org/wiki/Worldbuilding
Worldbuilding is the process of constructing an imaginary world or setting, sometimes associated with a fictional universe. Developing the world with coherent qualities such as a history, geography, culture and ecology is a key task for many science fiction or fantasy writers. Worldbuilding often involves the creation of geography, a backstory, flora, fauna, inhabitants, technology, and often if writing speculative fiction, different peoples. This may include social customs as well as invented languages (often called conlangs) for the world.
Vampire: The Masquerade - Bloodlines - probably the most cliche answer possible, but Troika really did build a game that took you to the world of vampires in LA in the early 2000s.
Arcanum - a fantasy world undergoing industrialization with technology being in direct conflict with magic.
UnderRail - A society stuck underground connected by tunnels between towns/cities and nodes. The writing (quests/characters) is not that great, but the world-building is top notch.
I’d add Redemption as well. It’s super rough now, but I played it 20 years ago, and I was amazed by all the lore. I didn’t know until after I finished it, that the game was based on a TTRPG.