-
For
Custom Camera
views, you can cycle through them using “K” for next camera and "Shift+K" for previous camera -
As per
Fixed Camera
views, you can cycle through them using “A” for next camera and “Shift+A” for previous camera … but you must first switch to the fixed camera view. I suggest reading my post about how to do it here : Guide -- How to use keys to switch between: Quickviews & Freelook camera ... Also Drone Camera & Fixed views -
Finally, for “unsetting” custom camera, I guess, you may just click the reset forward view button (ctrl + space) and then hit the key used to assign the custom camera you want to reset/unset (Ex. Ctrl+Alt+1)