Canon is in second place, because of a large offering including the Canon C300 range with the C300 MkII taking hold as the camera choice for many producers and Directors. Its not all great news for Canon though, the Canon C200 has not taken off as a rental camera neither has their C500 MKII or more high end C700 models. But it still has the 1DX MKII, 1DX MKIII and at the ever popular 5D MKIII and 5D MKIV loved by videographers, camera oporators and photographer the world over.
What can be said for the GoPro being in third place on this list with the Hero Black 5, 6, 7 and 8 dominating the small action camera rental market with some productions requesting 4-6 of these little gems per hire. A great second camera to just rig up to complement your main camera and in many ways is responsible for getting that wow shot from a privileged perspective that your main camera could just not do.
Finally Blackmagic, the Ursa Mini has been a great success and finally seems to be a camera you can pick up and shoot on with out having to worry about battery life and clamping other bits to the camera to make it work.
We hope this helps your choice if you want to hire a camera. Remember we are always happy to offer advice about the right camera for your latest project.