I needed a mount for my scarlet 2i2 to declutter my desk, so I drew up this design, intended to mount wit 4 countersunk screws. The audio interface slides in and is held in place through a tight friction fit, sturdy enough to not move when inserting/removing an instrument cable, but loose enough to remove the device whenever needed. 

This is a 3rd generation 2i2, but the design should fit all devices with the same 175mm x 45mm geometry.

The design comes in the correct print orientation and prints without supports:

I printed it on my Voron 2 in Prusament Galaxy Black ASA, but PETG or PLA should also be suitable. Slice with at least 3 perimeters and at least 40% infill.