Stroboframe is a well respected brand for flash brackets.
Really Right Stuff has some good ones as well.
Besides the old 'L style' brackets, there are two main types. Flip and Camera-rotate. The flip style brackets have a hing on the arm, so that when you rotate the camera, you can rotate the arm, putting the flash back above the lens. With the camera-rotate type, the flash stays stationary and the camera rotates on a couple small arms.
Either way, the flash ends up above the lens in horizontal or vertical orientation.
Besides looking for a good quality bracket, you want one that will be comfortable for you to use. Many of them have a handle, but I personally don't like that because I want to have one hand on the grip/shutter and the other hand on the lens. The bracket I use, is a Stroboframe Press-T, it's made so that instead of a handle, you keep both hands on the camera.
Also keep in mind that you'll probably want an anti-twist mounting plate. These are often sold separately because they have to fit your specific size of camera. They attach between the camera and the bracket, keeping the camera & bracket from twisting.
And you will certainly need and off-shoe cord to attach the flash to the hot-shoe.