This Raspberry Pi mount is designed from a B model, but similar models will fit as well (such as B+). It fits inside a V-slot on the Ender 3 family, and allows using all of the RasPi ports.

V-slot model from: Ender 3 Pro V-Slot covers by ximes - Thingiverse

Raspberry model for designing from: Raspberry Pi 3 Reference Design Model B Rpi Raspberrypi by alexandre_willame - Thingiverse