I actually love IVAN, and I feel like it has been completely forgotten https://github.com/Attnam/ivan

Widelands is a good game in the style of Settlers 2.

(The later games in The Settlers series moved away from the distribution-network style of gameplay in S2; so Widelands how carries that torch.)

Battle for westnoth !

And I can't remember right now the stealth game I used to play, it was the dark something, gonna search it later.

NetHack - Roguelike

Space Cadet Pinball - Decompilation of 3D Pinball for Windows – Space Cadet

The Battle for Wesnoth - Turn-based strategy game with a high fantasy theme

Mindustry - Sandbox tower-defense game

Minetest - Voxel game engine