I had need for a Vertically-oriented Phone Holder, so decided to whip one up in the same style as the one included with the Turntable Phone Mount. Just like that one, it comes with a GoPro style attachment.

Printing
 

I printed in .15 Quality mode just because I was concerned with the overhangs on the rubber band pegs; I felt printing the peg upside down was more reasonable than on its side with supports across its length, but honestly it's hard to say whether I'm right about that. The main body gets printed flat on its back with supports everywhere.

Assembly

Just slide it together and attach a rubber band. If you need to tension your rubber band, I've got a super simple rubber band tensioner.