Games like IXION
Games like IXION include Frostpunk, Oxygen Not Included, Manor Lords, Kingdoms and Castles, and Space Haven. We matched them by the tags players give IXION on Steam (Space, City Builder, Strategy, Survival, and Resource Management): closest matches first, and among equally close ones the better-known games.

Frostpunk
Shared: City Builder · Survival · Strategy

Oxygen Not Included
Shared: Survival · Colony Sim · Resource Management

Manor Lords
Shared: City Builder · Strategy · Base Building

Kingdoms and Castles
Shared: City Builder · Resource Management · Colony Sim

Space Haven
Shared: Space · Strategy · Survival

Banished
Shared: City Builder · Strategy · Colony Sim

Planetbase
Shared: City Builder · Space · Colony Sim

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

Frostpunk 2
Shared: City Builder · Strategy · Survival

Endzone - A World Apart
Shared: City Builder · Strategy · Survival

RimWorld
Shared: Strategy · Survival · Colony Sim

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

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

Settlement Survival
Shared: City Builder · Survival · Colony Sim

Dyson Sphere Program
Shared: Space · Resource Management · Base Building

Prison Architect
Shared: Strategy · City Builder · Building

Foundation
Shared: City Builder · Strategy · Simulation

Dwarf Fortress
Shared: Strategy · City Builder · Colony Sim

Empires of the Undergrowth
Shared: Strategy · City Builder · Base Building

Farthest Frontier
Shared: City Builder · Strategy · Resource Management

Cities: Skylines
Shared: City Builder · Strategy · Building

This War of Mine
Shared: Survival · Strategy · Base Building

Ostriv
Shared: City Builder · Strategy · Colony Sim

Dawn of Man
Shared: City Builder · Strategy · Survival