Games like Yggdrasil
Games like Yggdrasil include The Forest, Rust, Terraria, ARK: Survival Evolved, and Scrap Mechanic. We matched them by the tags players give Yggdrasil on Steam (Casual, Indie, Adventure, Early Access, and Action): closest matches first, and among equally close ones the better-known games.

The Forest
Shared: Adventure · Open World · Building

Rust
Shared: Crafting · Building · Open World

Terraria
Shared: Sandbox · Adventure · Building

ARK: Survival Evolved
Shared: Adventure · Open World · Building

Scrap Mechanic
Shared: Building · Sandbox · Open World

ARK: Survival Ascended
Shared: Open World · Adventure · Building

Raft
Shared: Building · Survival · Adventure

Slime Rancher
Shared: Adventure · Open World · Casual

Sons Of The Forest
Shared: Open World · Survival · Building

Starbound
Shared: Adventure · Sandbox · Crafting

TerraTech
Shared: Building · Sandbox · Open World

Don't Starve
Shared: Adventure · Indie · Crafting

Palworld
Shared: Open World · Indie · Adventure

No Man's Sky
Shared: Open World · Adventure · Sandbox

Once Human
Shared: Open World · Action · Building

Core Keeper
Shared: Open World · Sandbox · Survival

Last Oasis
Shared: Adventure · Action · Indie

The Long Dark
Shared: Adventure · Open World · Survival

Valheim
Shared: Building · Open World · Survival

The Infected
Shared: Early Access · Open World · Action

Green Hell
Shared: Action · Open World · Survival

My Time at Portia
Shared: Casual · Open World · Adventure

Stranded Deep
Shared: Adventure · Open World · Crafting

Conan Exiles Enhanced
Shared: Building · Open World · Survival