The LittleRP uses a custom one or two axis controller running Marlin but any normal 3D printer controller can be used to drive it. It has mounting holes 60mm apart on the back so I modified an existing holder for a Ardunino Mega board (on which the RAMPS board mounts) to work with the LittleRP.
This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/ivvniYA8H9e
Update 10/6: The tabs kept snapping off while threading the M5 bolts to mount it. I made them wider, thicker, and made the hole 8.5 mm so the bolts slide (mostly) through. They are anchored in threading on a rail on the other side so they don't need to screw into the tabs.