Games like Blockland
Games like Blockland include Garry's Mod, Grand Theft Auto V Legacy, Rust, Scrap Mechanic, and Grand Theft Auto V Enhanced. We matched them by the tags players give Blockland on Steam (Sandbox, Building, Multiplayer, Open World, and Action): closest matches first, and among equally close ones the better-known games.

Garry's Mod
Shared: Sandbox · Multiplayer · Building

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

Rust
Shared: Multiplayer · Open World · Building

Scrap Mechanic
Shared: Sandbox · Building · Multiplayer

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

Once Human
Shared: Open World · Multiplayer · Action

Terraria
Shared: Sandbox · Multiplayer · Building

Just Cause 2
Shared: Sandbox · Open World · Action

Far Cry 3
Shared: Open World · Multiplayer · Action

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

Raft
Shared: Multiplayer · Building · Open World

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

Space Engineers
Shared: Sandbox · Building · Open World

Arma 3
Shared: Multiplayer · Action · Open World

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

Wobbly Life
Shared: Multiplayer · Sandbox · Open World

Project Zomboid
Shared: Multiplayer · Open World · Sandbox

Human Fall Flat
Shared: Multiplayer · Sandbox · Funny

Mount & Blade II: Bannerlord
Shared: Open World · Sandbox · Multiplayer

Brick Rigs
Shared: Sandbox · Building · Multiplayer

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

POSTAL 2
Shared: Open World · Sandbox · First-Person

Far Cry® 4
Shared: Open World · Action · Multiplayer

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