This is a robust and solid holder for Elgato's Stream Deck (not the mini, not XXL).

UPDATE: Added a v3 almost vertical super tall variant (75 degrees) of the holder, this variant will probably require support to be printed (didn't test it myself yet).

UPDATE: After users testing the 75 degrees variant, there was a flaw in the design, but now it should be fixed.

Was frustrated with existing holder being to fiddly and collapsing on itself when I wanted to move it on the desk (tend to do it often). And seeing a lot of holders which are not steady enough, or have extra stuff I do not need or are just plain wasteful, have logos, unnecessary geometry (some are more ornaments and are more fashion statement than just a holder). So I decided to make my own function over the form holder, there are 4 variants of it, two with hollow bottom and two solid bottom and then each permutation with shallow angle and with steep angles (parametric source allow you to adjust your own angle, or do request in the comments).

I think the end result is versatile, rock-solid (the back is pretty wide so the stand will not wiggle even after some force), portable (has a separate cover which protects the buttons and slightly the USB cable as well and ability to bundle the cables inside), with no wasted material, so it should print pretty quick. No waste in ornaments or logos, just pure function. No post-processing needed after the print finished, no support needed to be printed as the overhangs are 45 degrees or less, works perfectly with 0.3mm resolution.

And the main point the Stream Deck feels solid in it, yet allows me more than even the improved version of the original stand. Only postprocessing or extra steps I did was put 4 rubber/silicone feet on it so the smooth plastic will not slide even on glossy surfaces.

Here is a demonstration video:
https://www.youtube.com/watch?v=eJKwI_28LYs

All configuration allow for a clip to be attached on top to keep it fixed in the holder, or bigger clip which will cover the whole keyboard (handy for transportation in a backpack), keeps the cable inside and protect it partially. These covers are optional and not really necessary for the holder to be useful.

Solidworks parametric sources included, so either do your own configuration, or ask in the comments for something.