There is one that works well, as long as you have an I pad. It is called Turbo Sounds. I use it with my 3X. You can download a free copy .
The free copy comes with three instruments...a bass, a choice guitar for chord section and if I remember correctly one right hand sound.
you can run this indefinitely as there is no time limit on it.. If you think you want some of his other instruments, you can try free before you purchase them. I have purchased only about four in the four plus years I have owned my copy. Only online support, BUT I have never had to wait more than over night for a solution to any issue I have had. Basically , you set up a band...of three or more instruments, name it, save it, then you can access it at any time with a touch of your finger. He also has an arranger part, which is really quite decent. For free, it is worth a try. I use mine during Oktoberfest season mostly, as it is much better suited to that type of music than my SD40. BUT it only works with an I Pad..... If you wish an actual piece of hardware, for my money go Ketron. I have used and still have the X-4, and Midjay plus, which I am contemplating passing along. the Midjay plus is rare as it has a swell/volume pedal that affects only the lead sound. I open the lid on its carry case, plug it in and play...no cords to worry about setting up...totally plug and play...I set my 40 up the same way.