If you search for sellmyapp Unity games, SellMyAppHub has multiple Unity 6 game source codes built for reskinning, mobile publishing, and fast customization.
Strong game types for reskinning
Puzzle games, block games, sorting games, cooking games, space shooters, match-3 games, and simple arcade projects are often easier to customize and launch than very complex projects.
What to check
Look for screenshots, gameplay style, number of levels, included assets, setup guide, documentation, and monetization potential.