I designed this adjustable iPhone&smartphone stand that is easy to assemble and still looks cute.

You can adjust the angle in 6 different ways. The distance where the phone sits is 7mm. My iPhone and the case together is about 9mm thick and it seems to fit fine. 

Please see the photos for assembly instruction.

Notes:

For printing the angle plate and the back plate, I recommend to use brim unless you have confidence in your bed levelling. You will also need support on the angle plate under the pins.

I printed all parts in both 0.1 and 0.2 layer height, worked fine either way but if you want a finer details especially the cat's pawa and ears on the base, I recommend to print in 0.1 layer height.

Smartphone stand angle plate and Smartphone stand back plate:
Brim:Yes
Support: Yes(only for angle plate)
Infill: 50%
Layer height: 0.1 or 0.2

Adjustable iPhone stand Base:
Brim and Support: No
Infill: 70%
Layer height: 0.1 or 0.2 (0.1 is recommended)