Let's keep a running tally of boxers that have tested positive at one time or the another for a performance enhancing drug. Let's only consider boxers that actually failed tests, not suspicions. It appears that a new name drops every few weeks. Here's a start although I'm sure that I'm missing a ton.

Brian Magee
J'Leon Love
Mickey Bey
Julio Cesar Chavez Jr.
Lamont Peterson
Erik Morales
Andre Berto
Antonio Tarver
Mariusz Wach
Sam Solimon
Shane Mosley
Ali Adams
Franz Botha
James Toney
Fernando Vargas
Roy Jones
Evander Holyfield
Orlando Salido