Mixers that are intended for live gig use with 1 or 2 aux outs. Also mixers that are intended for live gigs with only 1/4" aux outs.. Soundcraft got the Ui series right in a lot of respects. Even just the 16 has 4 aux outs. My 24r has 10. Granted 9/10 have to use the stereo headphone out but 8 XLR aux sends is still great. 4 IMO should be the minimum.