We like to use the iRig Blueboard midi controller with Sunday Guitar, but you can also use other controllers as long as they send midi. We like iRig Blueboard the best so we've done all the work for you and pre-assigned it with Sunday Guitar so you can plug in and play quickly.
Here are a couple other controllers folks like:
- The Apogee Gio: it functions as an audio interface and a midi controller. It works fine along with MainStage and Sunday Guitar, you will just want to assign the buttons in Layout mode to control different aspects of the template. It does have an expression pedal input, so you may look into getting an expression pedal that you can use as a volume pedal, especially if you plan to do any swells or ambient guitar stuff.
- Behringer FCB1010: this one does have extra buttons and two expression pedals. However, it is not very “user friendly” and can take a lot to program. We recommend spending a few extra dollars to get the iFCB software by Wabbit Wanch.