Who are the guys past and present who have gone from just average fighters early in their career to go on and be champions or top contenders?

Some names i can think of are

Antonio Margarito: Had 3 losses to no names in his first 12 fights.
Humberto Soto: Started his career 14-4-2, now 43-5-2.
Jhonny Gonzalez was 14-4-0, now 34-6-0
Jonny Nelson was 25-12-1, finished 45-12-2

I know i will have forgotten some obvious names. Who else has gone from a not so good beginning to a great fighter within their careers?