Games like Len's Island
Games like Len's Island include Terraria, Rust, The Forest, Valheim, and ARK: Survival Evolved. We matched them by the tags players give Len's Island on Steam (Open World Survival Craft, Survival, Farming, Building, and Dungeon Crawler): closest matches first, and among equally close ones the better-known games.

Terraria
Shared: Open World Survival Craft · Survival · Sandbox

Rust
Shared: Survival · Open World Survival Craft · Building

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

Valheim
Shared: Open World Survival Craft · Survival · Building

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

Raft
Shared: Survival · Open World Survival Craft · Building

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

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

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

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

Subnautica
Shared: Open World Survival Craft · Survival · Open World

Project Zomboid
Shared: Survival · Open World Survival Craft · Open World

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

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

Don't Starve
Shared: Open World Survival Craft · Survival · Crafting

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

ASTRONEER
Shared: Open World Survival Craft · Survival · Open World

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

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

Core Keeper
Shared: Survival · Open World · Building

Starbound
Shared: Open World Survival Craft · Survival · Sandbox

Stranded Deep
Shared: Open World Survival Craft · Survival · Open World

TerraTech
Shared: Open World Survival Craft · Building · Open World

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