I have been playing Time Snatcher Handy recently, a roguelike centered around a time-stop mechanic, which only uses 44 MB. It is pretty good. Going through my steam library from the lowest up, here are the others i would recommend, stopping at one GB, because most of my games are under 20 GB and i tend to be relatively selective with what games i get so i consider most of them good also:
- TIS-100 (80 MB), programming puzzle game by Zachtronics
- Islanders (150 MB), minimalist city builder
- Enter the Gungeon (346 MB), bullet-hell roguelike
- Streets of Rogue (417 MB), roguelike which emphasizes having multiple possible approaches for how to get any given objective
- Opus Magnum (493 MB), another Zachtronics programming puzzle game
- Vault of the Void (554 MB), roguelike deckbuilder (one of my most played games, especially recommended)
- Backpack Hero (616 MB), roguelike focused on maximizing adjacency bonuses on your inventory grid
- Urbek City Builder (685 MB), city builder (obviously)
- Slipways (735 MB), a game about optimizing trade routes between planets
- Cassette Beasts (1 GB), similar to Pokemon, with the main differences being that you turn into the monsters instead of summoning them, type advantage/disadvantage giving unique status effects rather than just changing damage and battles generally being 2v2 instead of 1v1