Packs suck, you are trying to sell the same things to every game dev from unity all the way down to our small community. You put a lot of work in to a product but want to sell it on a mass scale, like plush toys. However 3d games are unique and specialized, each demanding original content. So your business model sucks! As for fact, if you could sell enough of these models to the Unity users, you wouldn't even be on this site!

So how do you make money at the 3d model game.
1) create a large library of base models of many types and shapes
2) show the base model
3) accept customers sketches and designs for modifying you base into there og content
4) modify the base and sell the new mod with exclusive rights

Maybe you have sold 100 hell hound packs, but if i play 3 games with your same hell hounds I'll stop buying the unoriginal content from lazy devs and even lazier modelers.

Mal