Oddisee is one of the more positive artists out there.

Lecrae has some skills and obviously has content which is spiritually encouraging.

I haven't checked for K-Os in a while, but he had an album out this year and his lyrical content has always been positive.

Lupe's music is positive, but he does drop the occasional curse word.

I'm sure I'm missing some other contemporary rappers who are both positive and clean, but their name is escaping me.