A incomplete list of Steam games I really like:

RimWorld

A Hat in Time

Stardew Valley

Cities Skylines (1, obviously)

Two Point Hospital

Dont Starve

ES 4 Oblivion (and before you ask I do not care for Skyrim)

Fallout NV

Terraria (though ive never been able to beat it, I also like it modded)

Parkitect

Two Point Campus

Lego City Undercover

Planet Zoo

Oxygen Not Included

Plants vs Zombies

PvZ Garden Warfare 2

Necesse

Streets of Rogue

Kenshi

Modded Doom

Spiritfarer

Ty the Tasmanian Tiger

Tinykin

Yakuza

Age of Empires 2

Half Life saga