Games like Project Oasis
Games like Project Oasis include Frostpunk, Timberborn, Manor Lords, Kingdoms and Castles, and Captain of Industry. We matched them by the tags players give Project Oasis on Steam (Colony Sim, City Builder, Base Building, Building, and Automation): closest matches first, and among equally close ones the better-known games.

Frostpunk
Shared: City Builder · Colony Sim · Strategy

Timberborn
Shared: Colony Sim · City Builder · Automation

Manor Lords
Shared: City Builder · Base Building · Strategy

Kingdoms and Castles
Shared: Colony Sim · City Builder · Strategy

Captain of Industry
Shared: Base Building · Automation · Strategy

Prison Architect
Shared: Building · Colony Sim · Base Building

Factorio
Shared: Base Building · Automation · Strategy

Against the Storm
Shared: City Builder · Base Building · Strategy

Oxygen Not Included
Shared: Colony Sim · Base Building · Building

They Are Billions
Shared: Colony Sim · Base Building · Strategy

Workers & Resources: Soviet Republic
Shared: City Builder · Base Building · Strategy

Dyson Sphere Program
Shared: Base Building · Automation · Building

Empires of the Undergrowth
Shared: Base Building · City Builder · Colony Sim

Dwarf Fortress
Shared: Colony Sim · Base Building · City Builder

Farthest Frontier
Shared: City Builder · Building · Strategy

IXION
Shared: City Builder · Colony Sim · Strategy

Cities: Skylines
Shared: City Builder · Building · Strategy

Norland
Shared: City Builder · Colony Sim · Base Building

Ostriv
Shared: City Builder · Colony Sim · Strategy

Factory Town
Shared: Base Building · City Builder · Colony Sim

RimWorld
Shared: Colony Sim · Base Building · Strategy

Settlement Survival
Shared: City Builder · Colony Sim · Building

Kingdoms Reborn
Shared: Colony Sim · City Builder · Base Building

Endzone - A World Apart
Shared: City Builder · Base Building · Strategy