I did it for MacBook Pro 15" 2015 but it should work for most of 13" and other MacBooks as well. Thanks to those, your MacBook will be about 4cm higher - safe space on the desk or use it to make writing more comfortable.

You can try and print it with 10% infill. However, for me, the smaller holder was too weak and cracked.

I was inspired by MacBook Pro support designed by Gush. That one fits for me well but it was too unstable so that I decided to redesign it a little bit.