Games like Playcraft
Games like Playcraft include Rust, Terraria, Grand Theft Auto V Legacy, ARK: Survival Evolved, and Scrap Mechanic. We matched them by the tags players give Playcraft on Steam (Sandbox, Adventure, Massively Multiplayer, Action, and Multiplayer): closest matches first, and among equally close ones the better-known games.

Rust
Shared: Multiplayer · Sandbox · Adventure

Terraria
Shared: Sandbox · Multiplayer · Adventure

Grand Theft Auto V Legacy
Shared: Action · Multiplayer · Open World

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

Scrap Mechanic
Shared: Sandbox · Building · Multiplayer

Don't Starve Together
Shared: Multiplayer · Adventure · Sandbox

Once Human
Shared: Multiplayer · Action · Open World

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

Raft
Shared: Multiplayer · Adventure · Co-op

Palworld
Shared: Multiplayer · Open World · Adventure

Conan Exiles Enhanced
Shared: Sandbox · Open World · Building

Cultivation Tales
Shared: Sandbox · Action · Massively Multiplayer

Last Oasis
Shared: Massively Multiplayer · Adventure · Action

Wobbly Life
Shared: Adventure · Sandbox · Multiplayer

Just Cause 2
Shared: Sandbox · Action · Adventure

Valheim
Shared: Multiplayer · Open World · Building

Garry's Mod
Shared: Sandbox · Multiplayer · Building

Just Cause™ 3
Shared: Action · Multiplayer · Open World

Human Fall Flat
Shared: Adventure · Sandbox · Multiplayer

Monster Hunter: World
Shared: Action · Multiplayer · Adventure

Sons Of The Forest
Shared: Multiplayer · Open World · Co-op

Project Zomboid
Shared: Sandbox · Multiplayer · Open World

Red Dead Redemption 2
Shared: Adventure · Multiplayer · Open World

Grand Theft Auto IV: The Complete Edition
Shared: Action · Adventure · Open World