I designed this simple stand to hold a coin vertically after I got my Kickstarter Fibonacci Coins. Of course there are tons of coin stands on Thingiverse already, but this one meets my criteria.

I've included the f3d file which you can edit with Fusion 360. The relevant parameters are named so you can open the parameter list and make a few changes to make this fit any of your collectible challenge coins, currency, art, etc.

Pro tip - add 0.2mm to each coin dimension for a perfect fit.

Enjoy!