I have made some card sticker sets for Free! & SnK!
They're 85x 54mm in size and waterproof with thickness of approximately 0.05mm. You can stick them onto your fare pass, membership card etc.!
And they're reusable if you remove them carefully (just don't fold it).
Get them at my storenvy
By the way I just opened a service for customizing card stickers.
So you can make your arts & photo into card stickers too!
And you can have UNLIMITED number of design!
Visit here for more information.