Games like No One's Island
Games like No One's Island include Rust, The Forest, Valheim, ARK: Survival Ascended, and Once Human. We matched them by the tags players give No One's Island on Steam (Building, Fishing, Open World, Survival, and Character Customization): closest matches first, and among equally close ones the better-known games.

Rust
Shared: Survival · Open World · Building

The Forest
Shared: Survival · Open World · Building

Valheim
Shared: Survival · Open World · Building

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

Once Human
Shared: Open World · Survival · Building

Enshrouded
Shared: Open World · Survival · Building

Conan Exiles Enhanced
Shared: Open World · Building · Survival

Terraria
Shared: Survival · Building · Open World

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

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

Palworld
Shared: Open World · Survival · Crafting

Kenshi
Shared: Open World · Survival · Building

Core Keeper
Shared: Open World · Survival · Exploration

V Rising
Shared: Open World · Survival · Building

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

Last Oasis
Shared: Open World · Survival · Building

Scrap Mechanic
Shared: Building · Survival · Open World

Raft
Shared: Survival · Building · Open World

Craftopia
Shared: Open World · Survival · Building

RuneScape: Dragonwilds
Shared: Open World · Survival · Building

TerraTech
Shared: Building · Open World · Survival

Far Cry® Primal
Shared: Open World · Survival · Exploration

DYSMANTLE
Shared: Open World · Survival · Crafting

Project Zomboid
Shared: Survival · Open World · Building