Games like Outpost
Games like Outpost include Bloons TD 6, Dyson Sphere Program, Kingdom Rush Origins - Tower Defense, Rogue Tower, and Plants vs. Zombies GOTY Edition. We matched them by the tags players give Outpost on Steam (Casual, Tower Defense, Shoot 'Em Up, 2.5D, and Cartoony): closest matches first, and among equally close ones the better-known games.

Bloons TD 6
Shared: Tower Defense · Casual · Cartoony

Dyson Sphere Program
Shared: Space · Building · Base Building

Kingdom Rush Origins - Tower Defense
Shared: Tower Defense · Casual · Building

Rogue Tower
Shared: Tower Defense · Casual · Base Building

Plants vs. Zombies GOTY Edition
Shared: Tower Defense · Casual · Singleplayer

Mindustry
Shared: Tower Defense · Base Building · Building

Hydroneer
Shared: Base Building · Mining · Casual

Kingdom Two Crowns
Shared: Tower Defense · Building · Base Building

Kingdom Rush - Tower Defense
Shared: Tower Defense · Casual · Singleplayer

ShapeHero Factory
Shared: Tower Defense · 2.5D · Base Building

They Are Billions
Shared: Tower Defense · Base Building · Building

Plants vs. Zombies™: Replanted
Shared: Tower Defense · Casual · Cartoony

Creeper World 4
Shared: Tower Defense · Building · Space

Star Birds
Shared: Casual · Base Building · Building

Kingdom Rush 5: Alliance TD
Shared: Tower Defense · Cartoony · Building

Broken Universe - Tower Defense
Shared: Tower Defense · Casual · Building

Garry's Mod
Shared: Casual · Building · Singleplayer

Kingdom Rush Frontiers - Tower Defense
Shared: Tower Defense · Casual · Singleplayer

Gas Station Simulator
Shared: Casual · Building · Base Building

The Riftbreaker
Shared: Tower Defense · Base Building · Building

Bee Island
Shared: Tower Defense · Building · Base Building

Apocalypse Party
Shared: Casual · Shoot 'Em Up · Singleplayer

shapez
Shared: Base Building · Resource Management · Casual

Passpartout: The Starving Artist
Shared: Casual · Hand-drawn · Singleplayer