Games like 30 days to survive
Games like 30 days to survive include Project Zomboid, The Forest, 7 Days to Die, SCUM, and Miscreated. We matched them by the tags players give 30 days to survive on Steam (Simulation, Survival, Zombies, Post-apocalyptic, and Open World Survival Craft): closest matches first, and among equally close ones the better-known games.

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

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

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

SCUM
Shared: Survival · Open World Survival Craft · Zombies

Miscreated
Shared: Survival · Open World Survival Craft · Zombies

Days Gone
Shared: Zombies · Survival · Post-apocalyptic

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

Rust
Shared: Survival · Open World Survival Craft · Crafting

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

Mist Survival
Shared: Survival · Zombies · Open World Survival Craft

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

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

DayZ
Shared: Survival · Zombies · Post-apocalyptic

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

Raft
Shared: Survival · Open World Survival Craft · Crafting

SURVIVAL: Postapocalypse Now
Shared: Survival · Open World Survival Craft · Post-apocalyptic

Terraria
Shared: Survival · Open World Survival Craft · Crafting

Dying Light
Shared: Zombies · Survival · Open World Survival Craft

How to Survive
Shared: Survival · Zombies · Open World Survival Craft

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

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

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

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

State of Decay: YOSE
Shared: Survival · Zombies · Post-apocalyptic