First things first. I love this game! I think it's very cute and fun and I want more of it! Reader is my favorite character design wise and I always pick him. Keep on trucking and keep doing amazing work, you got this! I believe in you! That is all, lol.
So this is just ideas that I had come up right off the top of my head and I would absolutely would love to see be added one day far in the future! Once You've done what you want to do first!
1. Milfs!!! Please, please, please add Milfs! One of my favorite transformations of all times is Milfs and if you added it I would love you forever! I jest but seriously it would make this one person on the internet very happy.
2.Dragons! I also really love dragons and there are many types of dragons to choose from so almost every character can there own little dragon type! Don't know if you're going anthro only but if so, dragon girls are Fiery Hot! (See what I did there)
3.Robots! You're using an anime ai art style and there's no robots? Come on!!!
4.BBWs. Not my personal favorite but I know there's always going to be someone who wants it so I'm just adding it for good measure.
5.Maids! Can't have a transformation game without Maids now can we?
6.Harpy! Now this could be a fun one! Maybe just like the anime monster musume?
7.Speaking of monster musume..... Centaurs, Driders, Slimes, Lamias, Mermaids.... There's a lot and I mean a lot! I recommend just going to the wiki for some Ideas.
And that's really it, I've run out of Ideas at this moment but I'm sure I'll think of more stuff to add later. And I'm curious what you and everyone has can come up with! Please just take you time and don't rush yourself, burnout sucks and I want to make sure that you're doing okay. So yeah these are just my little ideas for you to pick and choose if you want. Or none at all! From a new fan.