Games like SpaceCraft Brawl
Games like SpaceCraft Brawl include Cosmoteer: Starship Architect & Commander, Space Engineers, Forts, Tom Clancy's Rainbow Six Siege, and Elite Dangerous. We matched them by the tags players give SpaceCraft Brawl on Steam (Multiplayer, Space Sim, Sci-fi, Building, and Physics): closest matches first, and among equally close ones the better-known games.

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

Space Engineers
Shared: Building · Multiplayer · Physics

Forts
Shared: Multiplayer · Physics · Building

Tom Clancy's Rainbow Six Siege
Shared: PvP · Multiplayer · Action

Elite Dangerous
Shared: Space Sim · Sci-fi · Multiplayer

Rust
Shared: Multiplayer · PvP · Building

Counter-Strike 2
Shared: Multiplayer · Action · PvP

STAR WARS™ Empire at War - Gold Pack
Shared: Multiplayer · Sci-fi · Space

PUBG: BATTLEGROUNDS
Shared: Multiplayer · PvP · Action

Dota 2
Shared: Multiplayer · PvP · Action

WARDOGS
Shared: Multiplayer · PvP · Action

Apex Legends™
Shared: Multiplayer · PvP · Action

STAR WARS™ Battlefront™ II
Shared: Multiplayer · Sci-fi · Action

Garry's Mod
Shared: Multiplayer · Building · Physics

From the Depths
Shared: Building · Physics · Multiplayer

Besiege
Shared: Physics · Multiplayer · Building

Brick Rigs
Shared: Multiplayer · Building · Physics

Starbase
Shared: Space Sim · Building · Sci-fi

No Man's Sky
Shared: Multiplayer · Sci-fi · Space

Silica
Shared: Multiplayer · PvP · Sci-fi

Teardown
Shared: Multiplayer · Physics · Destruction

Omega Strikers
Shared: PvP · Multiplayer · Action

Natural Selection 2
Shared: Multiplayer · Sci-fi · Action

BattleBit Remastered
Shared: Multiplayer · PvP · Action