Yes, L brackets; some have two quick release mounts so you can flip the bracket 90 with the camera attached to the bracket. There are generic ones that can more or less work with any camera and there are some designed for specific cameras that are dimensioned such that the lens axis maintains alignment when flipped. I have a generic Manfrotto with their RC2 quick releases to match the rest of my stuff. There is a little adjustable stop on it that can help keep the camera parallel. There are also way more expensive ones (as usual). I feel better with the camera/lens center of gravity over the tripod head as opposed to hanging off the side by using the 3-axis head.

And if you want to really go overboard, I recall there are gizmos that are a sort of gimbal mount to allow turning the mounted camera through an arc.