I have uploaded 2 styles of the phone holder I designed a year ago. They are approx the same size, however the large version has a deeper phone nest. Print the regular for phones less than 0.55in (14mm) thick. Print the large for phones no thicker than 0.93in (23.5mm).
Made with PLA, print on its side. Supports will be needed in the gap on the phone nest portion. Infill isn't important, I have done it at 0%, 20%, 40%, and 100%. I would not recommend going beyond 2 outlines. Raft does help, but I have been successful a few times without.
Used Autodesk Inventor to make this model. Sliced and printed with Simplify 4.1 on a Fusion F400 and in Cura 3.6 on an Anet A8.