Games like Gaia
Games like Gaia include Valheim, Once Human, 7 Days to Die, No Man's Sky, and Terraria. We matched them by the tags players give Gaia on Steam (Base Building, Open World Survival Craft, Exploration, Procedural Generation, and Adventure): closest matches first, and among equally close ones the better-known games.

Valheim
Shared: Open World Survival Craft · Base Building · Exploration

Once Human
Shared: Open World Survival Craft · Action · Exploration

7 Days to Die
Shared: Open World Survival Craft · Base Building · Survival

No Man's Sky
Shared: Open World Survival Craft · Exploration · Procedural Generation

Terraria
Shared: Open World Survival Craft · Adventure · Exploration

The Forest
Shared: Open World Survival Craft · Adventure · Survival

Dune: Awakening
Shared: Open World Survival Craft · Exploration · Base Building

ARK: Survival Evolved
Shared: Open World Survival Craft · Base Building · Survival

Subnautica
Shared: Open World Survival Craft · Exploration · Base Building

Core Keeper
Shared: Exploration · Base Building · Survival

ASTRONEER
Shared: Open World Survival Craft · Base Building · Exploration

Raft
Shared: Open World Survival Craft · Base Building · Survival

Green Hell
Shared: Open World Survival Craft · Base Building · Survival

Conan Exiles Enhanced
Shared: Open World Survival Craft · Survival · RPG

Rust
Shared: Open World Survival Craft · Survival · Adventure

Subnautica: Below Zero
Shared: Open World Survival Craft · Exploration · Base Building

The Long Dark
Shared: Open World Survival Craft · Exploration · Survival

Satisfactory
Shared: Base Building · Exploration · Open World Survival Craft

Palworld
Shared: Open World Survival Craft · Survival · Base Building

Don't Starve Together
Shared: Open World Survival Craft · Adventure · Survival

Grounded
Shared: Open World Survival Craft · Base Building · Survival

ICARUS
Shared: Open World Survival Craft · Base Building · Exploration

Grounded 2
Shared: Base Building · Adventure · Open World Survival Craft

Enshrouded
Shared: Base Building · Exploration · RPG