Its a really specific fetish, but I recently got weirdly enamored with a setting where girls, (or some special all female race) can be turned into some smaller form and collected, I like cards the most but theres very little of that. The one big thing that I think would make a scenario perfect for me is making it so when you possess a girl in their smaller form, you can do lots of fun things with them, like fuse them together, mabye summon them with other cards to items to change how they manifest. Maybe you could summon them with a nurse outfit card to have them pre-dressed for you, or with a petrification card to summon them as a statue, idk. Really this is the one time where I think a fetish would be best as a hentai game and not just straight porn.