To be honest - I have no idea! I often see character designs, but also some fashion.
I also saw one deviant "selling" egg adopts. And when someone "bought" one of them, she would draw a fully-grown dragon following the egg-design, and which theme the buyer wanted to have. I really like that idea - but I think you should be quite good on what it "hatching" to do such a kind of adopt.
I have a small inkling that's why I'm making a poll. I'm guessing its like character trades or character designs people buy. In my day it used to be character design requests. I think the terminology changed with the age groups on here.