On a whim, I was reading about the Beanie Babies craze (and subsequent bust) of the 90's - and this quote from the Wikipedia entry struck me:
Following are key factors that contributed to the collectible nature of Beanie Babies:
- Unique creative elements
- Supply/demand
- Availability
- New releases / retirements
Basic stuff, for sure. But it's kind of incredible that they haven't yet tried selling Beanie Baby NFT's, for ultimate irony.