Games like Monster Battles
Games like Monster Battles include Backpack Battles, 9 Kings, Balatro, Slay the Spire, and Monster Train 2. We matched them by the tags players give Monster Battles on Steam (Roguelike Deckbuilder, Auto Battler, Turn-Based Tactics, Inventory Management, and Strategy): closest matches first, and among equally close ones the better-known games.

Backpack Battles
Shared: Auto Battler · Inventory Management · Roguelike Deckbuilder

9 Kings
Shared: Auto Battler · Strategy · Roguelike Deckbuilder

Balatro
Shared: Roguelike Deckbuilder · Roguelike · Strategy

Slay the Spire
Shared: Roguelike Deckbuilder · Roguelike · Strategy

Monster Train 2
Shared: Roguelike Deckbuilder · Roguelike · Turn-Based Tactics

Slay the Spire 2
Shared: Roguelike Deckbuilder · Roguelike · Strategy

Wretch: Divine Ascent
Shared: Auto Battler · Strategy · PvP

Despot's Game: Dystopian Battle Simulator
Shared: Auto Battler · Turn-Based Tactics · Roguelike

Vivid Knight
Shared: Roguelike Deckbuilder · Inventory Management · Roguelike

RACCOIN: Coin Pusher Roguelike
Shared: Roguelike Deckbuilder · Strategy · Roguelike

Into the Breach
Shared: Strategy · Turn-Based Tactics · Roguelike

Monster Train
Shared: Turn-Based Tactics · Roguelike · Roguelike Deckbuilder

Backpack Hero
Shared: Roguelike Deckbuilder · Inventory Management · Roguelike

Turnbound
Shared: Roguelike Deckbuilder · Auto Battler · Inventory Management

Alina of the Arena
Shared: Roguelike Deckbuilder · Turn-Based Tactics · Roguelike

Super Fantasy Kingdom
Shared: Auto Battler · Strategy · Roguelike

He is Coming
Shared: Auto Battler · Strategy · Roguelike

Meme Mayhem
Shared: Roguelike Deckbuilder · Auto Battler · Roguelike

LONESTAR
Shared: Turn-Based Tactics · Roguelike Deckbuilder · Strategy

Cobalt Core
Shared: Roguelike Deckbuilder · Strategy · Roguelike

Backpack Dungeon
Shared: Inventory Management · Auto Battler · Strategy

Luck be a Landlord
Shared: Roguelike Deckbuilder · Strategy · Roguelike

Wildfrost
Shared: Roguelike Deckbuilder · Turn-Based Tactics · Roguelike

StarVaders
Shared: Roguelike Deckbuilder · Turn-Based Tactics · Roguelike