Hi @simulacrumgames,
I don’t feel there is a way to use the assets properly, as they vary greatly in form and design. But, this is not a bad thing. It requires more imagination, cleverness, and creativity. This requirement is what draws my attention to using mixed assets in a full game of some sort.
I’m currently heavily invested into developing my primary game project and game assets for the marketplace myself. I would only make a slice time of such a project if it was a team project for something unique.