Honestly i don't have a favorite type, it depends on a lot of things like is it animated, which software is used, is it 2d or 3d, what do you do with it, is it completely disproportionate to the rest of the body or does it make some sense, what about the shape, what skin tone is it, is it human or an anthropomorphic creature, how are the nipples, what's the role of the character and the personality etc...
I don't know man i feel like you should just make something that you would like rather than focusing too much on what others want to see, there are all kinds of games already, unless you're creating a very extremely specific and forgotten kink focused game i think doing what you like is much better, if you try to cather to other people's preferences too much you'll end up at the same point you were at when you started because everybody has different preferences and you can't make everyone happy, do something you like, and if people want to try it, it will be there for them
In my opinion, do what you want, create a character you like and if you want it to have big boobs go for it, but keep in mind to not worry too much about what people will think, you'll never get to the end of it and you'll get burnt out extremely quickly, if you do what you want you'll feel more creative freedom, more relaxed and you'll be able to enjoy the process of creating the game a lot more, which from what i've seen almost always (if not always) results in a much better and almost always finished game and a much happier dev
Good luck with your game
