Games like Hallowlands
Games like Hallowlands include Terraria, The Forest, No Man's Sky, Rust, and Valheim. We matched them by the tags players give Hallowlands on Steam (Procedural Generation, Exploration, Hack and Slash, Dungeon Crawler, and Sandbox): closest matches first, and among equally close ones the better-known games.

Terraria
Shared: Sandbox · Open World Survival Craft · Exploration

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

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

Rust
Shared: Crafting · Open World Survival Craft · Sandbox

Valheim
Shared: Open World Survival Craft · Exploration · Building

Black Desert
Shared: Exploration · Sandbox · Action RPG

Minecraft Dungeons
Shared: Hack and Slash · Dungeon Crawler · Exploration

鬼谷八荒 Tale of Immortal
Shared: Sandbox · Management · Exploration

Core Keeper
Shared: Exploration · Sandbox · Crafting

Starbound
Shared: Sandbox · Open World Survival Craft · Exploration

Moonlighter
Shared: Hack and Slash · Dungeon Crawler · Procedural Generation

Chronicon
Shared: Hack and Slash · Dungeon Crawler · Procedural Generation

Len's Island
Shared: Open World Survival Craft · Dungeon Crawler · Building

TerraTech
Shared: Sandbox · Building · Open World Survival Craft

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

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

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

The Riftbreaker
Shared: Hack and Slash · Exploration · Sandbox

Minecraft Dungeons II
Shared: Dungeon Crawler · Hack and Slash · Exploration

Romestead
Shared: Procedural Generation · Crafting · Adventure

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

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

Forager
Shared: Open World Survival Craft · Sandbox · Crafting

Necesse
Shared: Open World Survival Craft · Sandbox · Crafting