Games like Zomboard
Games like Zomboard include Oxygen Not Included, They Are Billions, Prison Architect, RimWorld, and Frostpunk. We matched them by the tags players give Zomboard on Steam (Strategy, Colony Sim, Base Building, Simulation, and Tower Defense): closest matches first, and among equally close ones the better-known games.

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

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

Prison Architect
Shared: Simulation · Base Building · Colony Sim

RimWorld
Shared: Colony Sim · Base Building · Strategy

Frostpunk
Shared: Strategy · Colony Sim · Base Building

Dwarf Fortress
Shared: Colony Sim · Base Building · Strategy

Manor Lords
Shared: Strategy · Base Building · Simulation

Against the Storm
Shared: Strategy · Simulation · Base Building

Kingdoms and Castles
Shared: Colony Sim · Strategy · Simulation

Factorio
Shared: Base Building · Strategy · Resource Management

Banished
Shared: Colony Sim · Strategy · Simulation

Empires of the Undergrowth
Shared: Strategy · Base Building · Simulation

Infection Free Zone
Shared: Base Building · Strategy · Zombies

Rise to Ruins
Shared: Colony Sim · Strategy · Tower Defense

Captain of Industry
Shared: Base Building · Strategy · Simulation

Stranded: Alien Dawn
Shared: Base Building · Strategy · Simulation

Kingdom Two Crowns
Shared: Tower Defense · Base Building · Strategy

Ostriv
Shared: Strategy · Simulation · Colony Sim

Workers & Resources: Soviet Republic
Shared: Strategy · Base Building · Simulation

Space Haven
Shared: Colony Sim · Base Building · Strategy

Colony Survival
Shared: Colony Sim · Base Building · Strategy

Castle Story
Shared: Strategy · Colony Sim · Building

Norland
Shared: Strategy · Simulation · Base Building

Diplomacy is Not an Option
Shared: Base Building · Colony Sim · Zombies