NFTs can be created as numbered sets, also.
You could sell limited-edition grumpy frog NFTs for each unique saying. For instance, create a limited edition of 100 grumpy frogs saying "I hate Mondays!" with a guarantee to never create another set with that same saying. I would sell #1 last (because it should be the most valuable one -- thus you want to let #s 2 - 100 help establish the price of #1).
I believe you can also set up the #1 NFT in each set to collect a portion of the future royalties for every other one in the set (just like you, the creator, can establish a creator's royalty percentage). Hold onto #1 until the others sell, then the built-in royalties received by the #1 token will make it even more valuable.
Could also pre-sell NFTs with a unique saying (determined by the original buyer). The original buyer gets #1. If the #1 has royalty rights on the rest, then the purchaser of #1 will be a natural salesperson for the rest of the set.
Just some random thoughts ...
RE: Selling Physical Products for HIVE!