The following freestyles represent pretty much represent the majority of styles that one could emulate in Rap. Mastering or at least being aware of each of these is the beginning of being the best as a lyricist.
Freestyles by Nas, Erule, Biggie, Tupac, Big L, Redman, Shyheim, Missy, Busta, Rapsody, The Fugees, Jean Grae, Kurupt, Eminem, Jay Z, Jaz O + more.
The Brooklyn Word 