TASMON: Taskbar Monsters

The developers describe how their game uses AI generated content like this:

Some character art, icons, and store capsule/key-art images in this game were created with the help of generative AI tools (Google Gemini). All AI-generated assets were reviewed, curated, and edited by the developer, and do not misuse third-party copyrighted works. No AI content is generated live for players at runtime — all assets are pre-generated and fixed.

Required on Steam store pages since 2024. It covers content that ships in the game, on its store page or in its marketing — Valve does not require a disclosure for AI tools used during development, so this says nothing either way about how the game was made. Check it on Steam.