I'm working on a postcard maker for museum collection artworks in the creative commons. It's in a phase where I'm looking to get feedback from people who might like to use it. Right now it only sends mail in the US. I've integrated the Met, Cleveland Museum of Art and AIC, with an experimental feature for Wikimedia Commons.

You can find the CC0 postcard app here: https://sweetpost.art/ but if you want to go the extra step you can install the Chrome extension and see what comes up: https://chromewebstore.google.com/detail/new-tab-new-art/old...

edit to add Firefox addon: https://addons.mozilla.org/en-US/firefox/addon/new-tab-new-a...

If you want to send a postcard you can use the promo: 1BUCK to send a postcard for a dollar to whoever in US. Any feedback or questions are welcome.