Games like Cat Guardian
Games like Cat Guardian include They Are Billions, Stacklands, Factorio, Oxygen Not Included, and Frostpunk. We matched them by the tags players give Cat Guardian on Steam (Strategy, Tower Defense, Survival, Card Game, and Resource Management): closest matches first, and among equally close ones the better-known games.

They Are Billions
Shared: Strategy · Survival · Tower Defense

Stacklands
Shared: Card Game · Survival · Strategy

Factorio
Shared: Strategy · Resource Management · Base Building

Oxygen Not Included
Shared: Survival · Resource Management · Base Building

Frostpunk
Shared: Survival · Strategy · Resource Management

Mindustry
Shared: Tower Defense · Strategy · Resource Management

Plants vs. Zombies GOTY Edition
Shared: Tower Defense · Strategy · Casual

Balatro
Shared: Card Game · Strategy · Roguelite

The King is Watching
Shared: Tower Defense · Strategy · Base Building

Slay the Spire
Shared: Card Game · Strategy · Card Battler

Diplomacy is Not an Option
Shared: Resource Management · Survival · Base Building

RimWorld
Shared: Strategy · Survival · Base Building

Against the Storm
Shared: Strategy · Base Building · Resource Management

Slay the Spire 2
Shared: Card Game · Strategy · Deckbuilding

Tower Dominion
Shared: Strategy · Tower Defense · Base Building

Manor Lords
Shared: Strategy · Base Building · Resource Management

Grim Nights
Shared: Strategy · Tower Defense · Survival

This War of Mine
Shared: Survival · Strategy · Resource Management

Infection Free Zone
Shared: Strategy · Base Building · Survival

The Alters
Shared: Survival · Strategy · Base Building

Bloons TD 6
Shared: Strategy · Tower Defense · Casual

Inscryption
Shared: Card Game · Strategy · Card Battler

Sheltered
Shared: Survival · Strategy · Base Building

Kingdoms and Castles
Shared: Strategy · Resource Management · Base Building