This is a very simple Stream Deck stand and there are many, but I didn't find one that had the right height and angle for my purposes, i.e. between the halves of a tented Moonlander keyboard. It fits the Stream Deck Mk2—I can't vouch for fit with any other models.

I designed this with Morphi for iPadOS. I've successfully printed it after slicing with Creality Slicer, using PLA+ on my Ender 3. The supports are just for the hole in the back that admits the USB cord. I'm not sure that's necessary, but it seemed prudent and adds very little material. The squares on the bottom of the frame are for affixing rubber feet or 2-sided tape or whatever you wish.