Games like Alien Extraction
Games like Alien Extraction include Aliens: Dark Descent, FTL: Faster Than Light, Stellaris, RimWorld, and XCOM: Enemy Unknown. We matched them by the tags players give Alien Extraction on Steam (Strategy, Funny, Sci-fi, Puzzle, and Aliens): closest matches first, and among equally close ones the better-known games.

Aliens: Dark Descent
Shared: Strategy · Sci-fi · Aliens

FTL: Faster Than Light
Shared: Strategy · Sci-fi · Space

Stellaris
Shared: Strategy · Sci-fi · Space

RimWorld
Shared: Strategy · Survival · Sci-fi

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

Alien: Isolation
Shared: Sci-fi · Aliens · Stealth

Sid Meier's Civilization®: Beyond Earth™
Shared: Strategy · Sci-fi · Space

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

Portal
Shared: Puzzle · Sci-fi · Singleplayer

Portal 2
Shared: Puzzle · Singleplayer · Funny

Hardspace: Shipbreaker
Shared: Sci-fi · Space · Puzzle

Plants vs. Zombies GOTY Edition
Shared: Strategy · Singleplayer · Funny

Cosmoteer: Starship Architect & Commander
Shared: Sci-fi · Strategy · Singleplayer

XCOM®: Chimera Squad
Shared: Strategy · Sci-fi · Aliens

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

The Alters
Shared: Strategy · Sci-fi · Survival

Sins of a Solar Empire II
Shared: Strategy · Sci-fi · Space

I Expect You To Die
Shared: VR · Strategy · Puzzle

Homeworld 3
Shared: Strategy · Sci-fi · Space

STAR WARS™: Squadrons
Shared: VR · Sci-fi · Space

Oxygen Not Included
Shared: Survival · Strategy · Singleplayer

XCOM 2
Shared: Strategy · Sci-fi · Singleplayer

Half-Life: Alyx
Shared: VR · Sci-fi · Singleplayer

Totally Accurate Battle Simulator
Shared: Funny · Strategy · Singleplayer