Is there any on the design show thing?
I’m not sure that I understand your question. Are you trying to find shared vinyls? If so they are the first tab on Apply Decals.
Have you gone into the game storefront and searched?
Another good place to look around or request would be the Fantasy Painter’s Lounge sub-forum.
Chances are, since most people likely don’t know what Homestuck is, that there isn’t a lot of related vinyls for it. You could always request some or make some to share yourself.