Games like The Last Starship
Games like The Last Starship include Oxygen Not Included, Dyson Sphere Program, RimWorld, Prison Architect, and Space Haven. We matched them by the tags players give The Last Starship on Steam (Space, Simulation, Building, Strategy, and Sandbox): closest matches first, and among equally close ones the better-known games.

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

Dyson Sphere Program
Shared: Space · Building · Simulation

RimWorld
Shared: Strategy · Base Building · Sandbox

Prison Architect
Shared: Simulation · Building · Sandbox

Space Haven
Shared: Space · Strategy · Simulation

Space Engineers
Shared: Space · Building · Sandbox

Kerbal Space Program
Shared: Space · Simulation · Sandbox

Stellaris
Shared: Space · Strategy · Sci-fi

Cities: Skylines
Shared: Simulation · Building · Strategy

Manor Lords
Shared: Simulation · Strategy · Base Building

Planetbase
Shared: Space · Strategy · Simulation

Jurassic World Evolution
Shared: Building · Simulation · Strategy

Against the Storm
Shared: Simulation · Strategy · Building

Spacebase DF-9
Shared: Space · Simulation · Strategy

Jurassic World Evolution 2
Shared: Building · Simulation · Sandbox

The Crust
Shared: Space · Base Building · Sandbox

Dwarf Fortress
Shared: Simulation · Strategy · Base Building

Empires of the Undergrowth
Shared: Simulation · Strategy · Building

Cities: Skylines II
Shared: Simulation · Building · Sandbox

Cosmoteer: Starship Architect & Commander
Shared: Space · Building · Sci-fi

IXION
Shared: Space · Strategy · Building

Kingdoms and Castles
Shared: Simulation · Strategy · Building

X4: Foundations
Shared: Space · Simulation · Sandbox

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