I know you said songs but you should really get all of these albums, all of them are worth the listen IMO.
Apathy - Primate Mindstate ( Underground Hip-hop )
ASAP Rocky - Live.Love.ASAP(East coast, Harlem trill )
Astronautalis - Pomegranate (Hiphop/indie, really good stuff if you enjoy stories )
Bad Meets Evil - Hell: The squeal ( Eminem & Royce da 5'9 )
Black Cobain - Young gifted and black ( Eastcoast Hiphop )
Black & Brown - Self titled ( Danny Brown & Black Milk, Amazing. )
The Cool Kids - When fish ride bicycles ( Chicago chill "swag" before it was popular )
Cunninlynguists - Oneirology ( Really good group, underground hip hop )
Danny Brown - XXX ( Odd voice, odd appearance, not many can touch him on the mic )
El-P - I'll Sleep When You're Dead ( Awesome production, underground hiphop )
Eyedea & Abilities - By the throat ( Awesome production, Amazing DJ )
Horseshoe Gang - ( Any remix they have done will kill your favorite rapper )
Iggy Azalea - Ignorant art ( Femcee from Aus )
Joe Budden - Mood Muzik 4 ( NJ hiphop, raw/emotional lyrics )
Jon Connor - Season 2 ( Raw east coast hiphop )
Kendrick Lamar - Section 80 ( The whole album is classic, he's the future of hiphop IMO )
Macklemore & Ryan Louis - The VS. EP ( Deep songs, great story telling )
Random Axe - Random Axe (Raw hiphop )
Royce da 5'9 - Success is certain
Schoolboy Q - Habits & Contradictions (along the lines of ASAP Rocky & Kendrick Lamar )
Tech n9ne - All 6's and 7's
Yelawolf - Trunk Muzik & Radioactive