Look at the first post of this thread. For an unrooted device, stay away from the moga and ps3 controllers; they will require root. The red samurai controllers from GameStop and Nyko Playpad series work great out of the box, and you can try them out in person at a GameStop store. The red samurai is priced well last I checked. Pretty much any wired PC, Xbox, or PS3 controller will work just fine out of the box as well, if you don't mind wires. And the Logitech 710 is wireless but will require you to attach a nano dongle to your OTG cable so it's not completely wireless. The 710 is a very well-made controller and supports rumble in MupenAE, though it's a bit bulky (a bit larger than an xbox or ps3 controller).