Games like Galaxy Life
Games like Galaxy Life include Age of Empires III: Definitive Edition, Foxhole, Starship Troopers: Terran Command, Stronghold Crusader HD (2012), and XCOM: Enemy Unknown. We matched them by the tags players give Galaxy Life on Steam (Strategy, City Builder, Wargame, Strategy RPG, and 2.5D): closest matches first, and among equally close ones the better-known games.

Age of Empires III: Definitive Edition
Shared: Strategy · City Builder · Military

Foxhole
Shared: Wargame · Strategy · Military

Starship Troopers: Terran Command
Shared: Strategy · Wargame · Military

Stronghold Crusader HD (2012)
Shared: City Builder · Strategy · Military

XCOM: Enemy Unknown
Shared: Strategy · Aliens · Sci-fi

XCOM 2
Shared: Strategy · Sci-fi · Tactical

Manor Lords
Shared: Strategy · City Builder · Base Building

Wargame: Red Dragon
Shared: Strategy · Wargame · Military

Heroes of the Three Kingdoms 7
Shared: Strategy · Strategy RPG · Wargame

Sid Meier's Civilization VII
Shared: Strategy · City Builder · Military

Age of Empires II (Retired)
Shared: Strategy · City Builder · Base Building

Thronefall
Shared: Strategy · City Builder · Isometric

Broken Arrow
Shared: Strategy · Wargame · Tactical

Two Point Campus
Shared: Strategy · City Builder · Cartoony

Mechabellum
Shared: Strategy · Wargame · Tactical

Halo Wars: Definitive Edition
Shared: Strategy · Base Building · Sci-fi

WARNO
Shared: Wargame · Strategy · Military

Frostpunk
Shared: City Builder · Strategy · Base Building

ZeroSpace
Shared: Wargame · City Builder · Strategy RPG

Game of Thrones Winter is Coming
Shared: Strategy · City Builder · Strategy RPG

Master of Command
Shared: Strategy · Strategy RPG · Wargame

Europa Universalis IV
Shared: Strategy · Wargame · Military

Becastled
Shared: Strategy · City Builder · Base Building

Company of Heroes 3
Shared: Strategy · Wargame · Military