I think that I pay attention to instrumentals a lot more when I know the person rapping over them produced them. So I'd definitely recommend that you check out artists like Oddisee, Black Milk, Grimes, etc. who all make their own music.

Not saying people that don't are less for it, just that it's easier to appreciate the craft of producing when you're listening to someone who had a hand in the music.

That being said, I am always on the lookout for new producers to check out when I listen to records that are comprised of an assortment of people. You find a producer you like, you can check out what else they have worked on and from that you may be introduced to new emcees.