A Tablet / Phone stand, I quickly created in fusion 360 for a friend. It is fully parameterizable. (Just import into Fusion and change the User Variables for your specific needs.)

The Fusion Project File is included.

Print either on the side with support for the cutout or standing flat on the build plate, if your printer supports those overhangs. I printed it flat on a Prusa i3 MK3 with 0.15mm layer height and it turned out great.

UPDATE v2: Just revised the Model to have a thicker frame and a higher border at the front, to hold the device in.

Print instructions

Category: Tablet Print Settings

Printer: Prusa i3 Mk3

Supports: No

Resolution: 0.15

Infill: 20%