PPC agents who have gone through regeneration include Morgan, the Agent, the Disentangler, the Notary, the Reader, the Guardsman, Tawaki Penguin, Tadkeeta, Natalie Green, and the Aviator (though the last four were not originally Time Lords).
Time Lord Sues often forget that regeneration has some unpleasant aftereffects, such as manic episodes, fainting spells, confusion, delirium, and poor coordination, among other things. This is a charge.
The Doctor has also been granted an extension in regenerations, as the recent specials have revealed that the Eleventh Doctor actually expended all thirteen lives. The Eighth Doctor apparently regenerated into the War Doctor (John Hurt), who regenerated into Nine, who regenerated into Ten. Ten regenerated during the season four finale, but managed to keep his current face and caused instead a metacrisis – but that was still considered a regeneration in the full scheme of things. Therefore, to regenerate Eleven into Twelve, the Time Lords of Gallifrey, who had been relocated into a parallel dimension instead of being destroyed and were attempting to contact the prime timeline through cracks in space and time, granted Eleven a new set of regenerations.