Black Gold - Shining Town

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

All character illustrations and CGs are fully hand-drawn by our art team. For some background artworks, AI tools were used only to generate initial drafts. All final visuals were manually refined, edited, and completed by our artists.

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.