MF Doom's Madvallainy is one of the greatest albums of all time, it's creativity, amazing production and stae of the art rapping makes it deserve top spot here.
Tech N9ne should be number 1 on this list, but the thing is, he's not really that underground because of the fact that mainstream is going Tech. But he should be number 1 on any list of hip hop artists for his consistency of releasing literally more albums than any other artist with more than 300 songs in his arsenal and his superior intricacy. He
Back in 1992 there were 9 record labels wanting to sign him, including Priority, Def Jam, No Limit and Jive... he ended up being banned from radio stations, studios and record labels and forbidden to play live for many years after that.. true story
Another veteran of the rap game, Slug is also a complex lyricist, and an incredible one. He stays true to hip hop with his clever rhymes and smooth flow.