I dunno, but from experience, a MM/Corr duo of any sort is a highly beneficial partnership.,
Ice/ice Corruptor might be good. 
I'm playing with a Necro/dark MM right now and Duoing random AE Arcs. It's working out pretty well. He has me malafactored to 46.
I'd have to say that any of the buffing sets would work well.
Necro pets are by and large melee focused, but are pretty squishy. Anything that helps them survive melee range is golden in my book.
Cold Domination, Thermal, and Sonic would be my picks for support.
As for the Primary, basically anything you want, though I would shy away from Energy due to it's knockback.
@Oathbound & @Oathbound Too
Hello all!
My roommate has a MM they want to work with some, and I was thinking of making a Corrupter to play with him. The MM is, I believe, Necro/ Dark.
Any opinions on what you think might work best with that? And maybe why? I'm open to most ideas, except the guns...I'm not fond of them. Thanks for any ideas!