Literally any STANAG AEG mags. ARES M4s aren't too picky when it comes to mags.
I have had one G&G mag that was a bit too tight when loaded so I filed it down a bit until it fit.
I've also had an ICS one that wiggled around inside the magwell. A little bit of tape on the inside solved that problem.
A few good brands are PTS, MAG (if you can find any), TM and G&G.