Hmm... That's a tough one. I'd say a mix of simple and complex ones. Have some complex ones that bring in the big bucks and some small ones for quick and easy cash.

As for adopts, I'd love to see some eastern style dragons. Some fat noodles XD

Thank you for your opinion! <3
Ooooo, noodles! It's a good idea!

With that, people will have options to fit their art budgets.

YES NOODLES! Especially robot noodles. I need to make one for myself XD

Agree with MAD as far as pricing and art complexity goes
As for adopts, kobolds and dinosaurs are also fun options (Though I'm biased haha, been on a kick wanting some hybrid kobolds xD)

I'd love to see a multi-char ych for pairings!

I'm not an expert on any of this, but I get the issue, especially considering how YCH's can be Hit or miss sometimes (you would know better then me)

I think some smaller/simpler YCH's that you can do many of quickly and charge a small amount for would be an option to go with, especially to allow those that can't normally afford big bidding wars to actually get something from you, but I don't think it can replace the bigger YCHs completely as they can bring in bigger amounts all at once.

I do agree with MAD and Trike that more species may be good to offer, like Dino's and Eastern Dragons. It may also help prevent burnout by getting to draw different things. I think more variety can also help attract more people. I have some other ideas but I can leave it there for now