Games like Half-Earth Socialism
Games like Half-Earth Socialism include Victoria 3, Democracy 4, Crusader Kings II, Europa Universalis IV, and Slay the Spire 2. We matched them by the tags players give Half-Earth Socialism on Steam (Simulation, Strategy, Card Game, Education, and Grand Strategy): closest matches first, and among equally close ones the better-known games.

Victoria 3
Shared: Simulation · Strategy · Grand Strategy

Democracy 4
Shared: Strategy · Simulation · Political Sim

Crusader Kings II
Shared: Strategy · Grand Strategy · Simulation

Europa Universalis IV
Shared: Strategy · Simulation · Grand Strategy

Slay the Spire 2
Shared: Card Game · Strategy · Roguelike

Balatro
Shared: Card Game · Strategy · Roguelike

Age of History 3
Shared: Strategy · Grand Strategy · Education

Age of History II
Shared: Strategy · Grand Strategy · Simulation

Victoria II
Shared: Strategy · Grand Strategy · Simulation

Imperator: Rome
Shared: Strategy · Simulation · Grand Strategy

Against the Storm
Shared: Simulation · Strategy · Grand Strategy

Manor Lords
Shared: Strategy · Simulation · Grand Strategy

Hearts of Iron IV
Shared: Strategy · Grand Strategy · Simulation

Slay the Spire
Shared: Card Game · Strategy · Roguelike

Europa Universalis V
Shared: Strategy · Simulation · Grand Strategy

Democracy 3
Shared: Simulation · Strategy · Political Sim

Stacklands
Shared: Card Game · Strategy · Roguelite

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

Sid Meier's Civilization VII
Shared: Strategy · Grand Strategy · Simulation

Crusader Kings III
Shared: Strategy · Simulation · Grand Strategy

Tropico 6
Shared: Strategy · Simulation · Political Sim

Empires of the Undergrowth
Shared: Simulation · Strategy · Grand Strategy

Stellaris
Shared: Strategy · Grand Strategy · Simulation

Cultist Simulator
Shared: Card Game · Simulation · Roguelike