Games like Expanse
Games like Expanse include Rusted Warfare - RTS, Circle Empires, Town of Salem, Wargame: Red Dragon, and Creeper World 3: Arc Eternal. We matched them by the tags players give Expanse on Steam (Strategy, Indie, Massively Multiplayer, and RTS): closest matches first, and among equally close ones the better-known games.

Rusted Warfare - RTS
Shared: Strategy · RTS · Indie

Circle Empires
Shared: Strategy · Indie · RTS

Town of Salem
Shared: Strategy · Indie · Massively Multiplayer

Wargame: Red Dragon
Shared: Strategy · RTS · Indie

Creeper World 3: Arc Eternal
Shared: Strategy · Indie · RTS

Tooth and Tail
Shared: Strategy · Indie · RTS

Shadow Tactics: Blades of the Shogun
Shared: Strategy · Indie · RTS

BidKing
Shared: Strategy · Massively Multiplayer · Indie

Age of Empires II (Retired)
Shared: Strategy · RTS

Total War: WARHAMMER III
Shared: Strategy · RTS

Plague Inc: Evolved
Shared: Strategy · Indie

Notes of Soul
Shared: Massively Multiplayer · Indie · Strategy

Foxhole
Shared: Massively Multiplayer · Strategy · Indie

Company of Heroes 2
Shared: Strategy · RTS

Total War: WARHAMMER II
Shared: Strategy · RTS

WARNO
Shared: Strategy · RTS · Indie

8-Bit Armies
Shared: Strategy · Indie · RTS

Screeps: World
Shared: Strategy · Massively Multiplayer · RTS

Infested Planet
Shared: Strategy · Indie · RTS

Steel Division 2
Shared: Strategy · RTS · Indie

Natural Selection 2
Shared: Strategy · RTS · Indie

Command & Conquer™ Remastered Collection
Shared: Strategy · RTS

Age of Empires III: Definitive Edition
Shared: Strategy · RTS

Ultimate General: Gettysburg
Shared: Strategy · RTS · Indie