Games like Avitium
Games like Avitium include Inscryption, Library Of Ruina, Griftlands, Slay the Spire 2, and Slay the Spire. We matched them by the tags players give Avitium on Steam (RPG, Strategy, Card Battler, Story Rich, and Turn-Based Combat): closest matches first, and among equally close ones the better-known games.

Inscryption
Shared: Card Battler · Story Rich · Card Game

Library Of Ruina
Shared: Story Rich · Strategy · Card Game

Griftlands
Shared: Card Battler · RPG · Deckbuilding

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

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

9 Kings
Shared: RPG · Strategy · Card Game

Sultan's Game
Shared: RPG · Strategy · Story Rich

Baldur's Gate 3
Shared: RPG · Story Rich · Turn-Based Combat

天外武林 (Traveler of Wuxia)
Shared: RPG · Card Battler · Strategy

Roguebook
Shared: RPG · Strategy · Card Game

Gordian Quest
Shared: RPG · Card Battler · Strategy

GWENT: The Witcher Card Game
Shared: Strategy · RPG · Card Game

Clair Obscur: Expedition 33
Shared: Story Rich · RPG · Turn-Based Combat

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

Chrono Ark
Shared: RPG · Strategy · Card Game

Super Fantasy Kingdom
Shared: RPG · Strategy · Card Game

Monster Train
Shared: Card Battler · Card Game · Deckbuilding

Balatro
Shared: Card Game · Strategy · Deckbuilding

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

觅长生
Shared: RPG · Strategy · Turn-Based Combat

The Witcher 3: Wild Hunt — Remastered
Shared: RPG · Story Rich · Third Person

Marvels Midnight Suns Digital Edition
Shared: Deckbuilding · Turn-Based Combat · RPG

Mount & Blade II: Bannerlord
Shared: Strategy · RPG · Medieval

Deep Sky Derelicts
Shared: RPG · Strategy · Card Battler