dont know what kind of style you have but for me i like to freestyle over

nas - nas is like
talib - get by
notorious big - skys the limit (i dont know why but i could rhyme for hours on that beat)
mobb deep - shook one
50 cent - many men (dope when he isnt ruining it)
jay-z - dead presidents (same as skys the limit)
notorious big - who shot ya
cormega - testamony (i think i spelled it wrong)

i dont know their is alot of dope beats if you jsut look