Do you already have plans/ideas for the potions you're going to add in future updates? If not, I'd suggest a potion to make her boobs grow, or maybe one to make her ass even bigger. And another idea that I had that might not be exactly what you're aiming for, but what if there was like a clone potion that would let Swinky grope and finger herself, since she clearly enjoys it, and maybe combined with the futa potion she could even fuck herself, but I don't know if that's the direction you'd want to take things. Just an idea in case you feel inspired by it.