Games like Farmageddon: Undead
Games like Farmageddon: Undead include Orcs Must Die! 3, Creeper World 4, World of Warships, Stronghold: Definitive Edition, and Plague Inc: Evolved. We matched them by the tags players give Farmageddon: Undead on Steam (Outbreak Sim, Third-Person Shooter, Real Time Tactics, Tower Defense, and Economy): closest matches first, and among equally close ones the better-known games.

Orcs Must Die! 3
Shared: Tower Defense · Third-Person Shooter · Strategy

Creeper World 4
Shared: Real Time Tactics · Tower Defense · Strategy

World of Warships
Shared: Third-Person Shooter · Shooter · 3D

Stronghold: Definitive Edition
Shared: Real Time Tactics · Strategy · Economy

Plague Inc: Evolved
Shared: Outbreak Sim · Strategy · Indie

Bloons TD 6
Shared: Tower Defense · Strategy · 3D

Stronghold HD (2012)
Shared: Real Time Tactics · Economy · Tower Defense

Orcs Must Die! 2
Shared: Tower Defense · Strategy · Third-Person Shooter

Stronghold Crusader: Definitive Edition
Shared: Real Time Tactics · Strategy · Tower Defense

Orcs Must Die!
Shared: Tower Defense · Strategy · Third-Person Shooter

Orcs Must Die! Deathtrap
Shared: Tower Defense · Third-Person Shooter · Physics

Children of the Sun
Shared: Real Time Tactics · Strategy · Third-Person Shooter

PUBG: BATTLEGROUNDS
Shared: Third-Person Shooter · Shooter · Strategy

Battle Cry of Freedom
Shared: Real Time Tactics · Third-Person Shooter · Shooter

Dead Space
Shared: Third-Person Shooter · Horror · Shooter

Attack on Toys
Shared: Third-Person Shooter · Real Time Tactics · Tower Defense

Shadow Tactics: Blades of the Shogun
Shared: Real Time Tactics · Strategy · Isometric

The Callisto Protocol™
Shared: Third-Person Shooter · Shooter · Horror

The Last of Us™ Part I
Shared: Third-Person Shooter · Shooter · Horror

Element TD 2 - Tower Defense
Shared: Real Time Tactics · Tower Defense · Strategy

Thronefall
Shared: Tower Defense · Strategy · 3D

Plants vs. Zombies: Battle for Neighborville™
Shared: Third-Person Shooter · Tower Defense · Shooter

Dead Space™ 2
Shared: Third-Person Shooter · Shooter · Horror

Minimalist Tower Defense
Shared: Tower Defense · Real Time Tactics · Strategy