Star Wars: Empire at War gets updated every year

dwarf fortress

cosmoteer
factorio
tales of maj'eyal

Phoenix Point
Descenders
Nuclear Throne

Half-Life

A lot of indie games are being updated for a long time. It's mostly AAA games that aren't. Some AAA games don't even get to grow old and are instead taken behind the shed to—I mean—be driven to the farm where they'll live happily ever after.

I believe the oldest game still being updated on the regular is Dwarf Fortress but that's just from my knowledge so it's probably wrong. Other games off the top of my head are; Cataclysm: Dark Days Ahead, Terraria, and…erm…sorry, that's all my head can remember off the top. :I

Chess occasionally gets mods every now and then.

What do you mean by "live service games" exactly?
Microtransactions? DLCs? Monthly subscription model? Any or all of these things?

To actually keep developing an older game way beyond the initial release, a business would need an incentive to do that. Which means that they will monetize it somehow. The only people who would do that without true business incentive would likely be indie developers to whom developing and providing QOL updates is also a hobby, not just a job.

Games I've noticed from my library are;

• Mutant Football League
  
• Death Road to Canada
  
• No Man's Sky
  
• Project Zomboid
  
• X4 Foundations
  
• Beam.NG Drive
  
• Terraria
  
• Don't Starve Together

https://psteamproxy.yuanyoumao.com/app/1091500/Cyberpunk_2077/


still get's updated

https://psteamproxy.yuanyoumao.com/app/1259420/Days_Gone/

got updated but was a bad update, they had to do a beta old version option download

Actually this brings to mind a specific game that's on steam, released in 2003.
Battle for Wesnoth, which is completely free and open source, it's a uhh, turn based strategy game, but it's actually really fun, and the devs still maintain it, even add a bunch of new things from time to time still.
https://psteamproxy.yuanyoumao.com/app/599390/Battle_for_Wesnoth/

Stellaris. This game's gameplay is completely overhauled approximately once a year, with all its mechanics being reworked.

引用自 Dom：

What do you mean by "live service games" exactly?

I meant Live Service Games.

If you're not familiar with what those are, then no explanation I offer you will help clarify.

Vigil: The Longest Night
Evochron Legacy

SWG Legends. They just updated the Life Day stuff.