Games like Under The Mask
Games like Under The Mask include Balatro, Slay the Spire 2, Slay the Spire, Into the Breach, and Monster Train. We matched them by the tags players give Under The Mask on Steam (Card Battler, Strategy, Turn-Based Tactics, Card Game, and Turn-Based Strategy): closest matches first, and among equally close ones the better-known games.

Balatro
Shared: Card Game · Strategy · Roguelike

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

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

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

Monster Train
Shared: Card Battler · Card Game · Turn-Based Tactics

Vampire Crawlers: The Turbo Wildcard from Vampire Survivors
Shared: Card Battler · Strategy · Roguelike

Inscryption
Shared: Card Battler · Card Game · Strategy

Wildfrost
Shared: Card Battler · Card Game · Turn-Based Tactics

Cobalt Core
Shared: Strategy · Card Game · Turn-Based Strategy

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

The Last Spell
Shared: Strategy · Turn-Based Strategy · Turn-Based Tactics

Dream of Corpse Lady
Shared: Strategy · Card Battler · Card Game

Your Only Move Is HUSTLE
Shared: Strategy · Turn-Based Strategy · Turn-Based Tactics

LONESTAR
Shared: Strategy · Card Battler · Turn-Based Tactics

Roguebook
Shared: Card Game · Strategy · Indie

Die in the Dungeon
Shared: Strategy · Roguelike · Card Game

Monster Train 2
Shared: Card Game · Strategy · Roguelike

As We Descend
Shared: Card Battler · Card Game · Turn-Based Tactics

9 Kings
Shared: Strategy · Card Game · Roguelike

Touhou: Lost Branch of Legend
Shared: Strategy · Card Battler · Card Game

Stray Path
Shared: Card Battler · Strategy · Card Game

Dungeons & Degenerate Gamblers
Shared: Strategy · Card Battler · Card Game

Cross Blitz
Shared: Card Battler · Card Game · Strategy

DICEOMANCER
Shared: Strategy · Card Battler · Card Game