Games like Terranny
Games like Terranny include Mechabellum, The Bazaar, GLADIABOTS - AI Combat Arena, Plague Inc: Evolved, and Backpack Battles. We matched them by the tags players give Terranny on Steam (Robots, Auto Battler, Simulation, Strategy, and Automation): closest matches first, and among equally close ones the better-known games.

Mechabellum
Shared: Auto Battler · Robots · Strategy

The Bazaar
Shared: Auto Battler · Strategy · Asynchronous Multiplayer

GLADIABOTS - AI Combat Arena
Shared: Strategy · Robots · Simulation

Plague Inc: Evolved
Shared: Simulation · Strategy · Singleplayer

Backpack Battles
Shared: Auto Battler · Strategy · PvP

Dyson Sphere Program
Shared: Automation · Simulation · Strategy

Sid Meier’s Civilization® VI
Shared: Strategy · Singleplayer · Simulation

Dota Underlords
Shared: Auto Battler · Strategy · Tactical

BattleTech
Shared: Strategy · Robots · Tactical

XCOM 2
Shared: Strategy · Tactical · Singleplayer

Totally Accurate Battle Simulator
Shared: Simulation · Strategy · Singleplayer

STAR WARS Zero Company™
Shared: Strategy · Singleplayer · Tactical

Desynced
Shared: Strategy · Automation · Programming

Sins of a Solar Empire II
Shared: Strategy · Singleplayer · Tactical

Captain of Industry
Shared: Automation · Simulation · Strategy

shapez 2 - Factory
Shared: Automation · Strategy · Simulation

STAR WARS™ Empire at War - Gold Pack
Shared: Strategy · Singleplayer · Tactical

Oaken Tower
Shared: Auto Battler · Strategy · Asynchronous Multiplayer

Cities: Skylines
Shared: Simulation · Strategy · Singleplayer

Phantom Brigade
Shared: Simulation · Robots · Strategy

Eslabong
Shared: Auto Battler · Strategy · Tactical

Warhammer 40,000: Battlesector
Shared: Strategy · Tactical · Singleplayer

Nimbatus - The Space Drone Constructor
Shared: Strategy · Robots · Singleplayer

Hearts of Iron IV
Shared: Strategy · Simulation · Tactical