I know this is kind of old but I just found it and thought it interesting.
For one, I could definitely see a bunch of Hello Kitty crossovers, Sanrio loves cross-promotion after all
Whether that would be special Hello Kitty style clothes, little charms, or even a pony that was designed like Hello Kitty and all her friends, I could totally see it.
If it was present-day we're talking about, then I can definitely see them doing squishies or something like that since it's a trendy toy and there's some Hello Kitty squishies as well.
Probably plushes and maybe blind bags since that's an industry standard at this point?
If we were lucky maybe even a TV Show
These are all my hypothesis though. I don't know too much about Sanrio though, so apologies if I messed something up