I think it is just Kim Kunkel creating the templates.  I've bought templates from her before and had a couple conversations.  She is one of the few Americans who has hockey templates.  (I seem to remember she dabbled a bit in micro a few years ago.)    (edit LEO I remember telling her about Symbiostock back in the day not sure if she tried it  )

www.myphotoborders.com is another good one to buy sports templates.

Sean DeMint runs this one:  https://photosolutionsmarket.com/  He DOES have a vendor's mall, but I haven't looked into applying or if it's just some of his buddies work for sale on his site.  He runs a facebook group I'm in and seems pretty approachable.