I think he's talking about the altcoins.
You can find the top ones here:
https://coinmarketcap.com/You might want to consider making the top 5 or so..
Anything not
BTC will be made to order. I've yet to sell a single
BTC stamp. It ties up working capital to make a new product in advance. Where doing made to order costs nothing up front. If anyone wants any other alt-coin stamps, or anything else for that matter, it is just a matter of letting me know what you want, and I will make it for you.