The Master (First Frontier)

The Master was given a new body by the Tzun which allowed him to regenerate into a new body.

Biography
The Master's previous incarnation escaped the Cheetah planet and made a deal with the Tzun which involved the Master helping the Tzun to invade Earth in exchange for the Tzun building a new body for the Master.

The Tzun accepted and the Master was given nanites that broke down the corrupted Trakenite DNA in his cells and restructure it. This restored the Master to being a "full" Time Lord which gave him a new regenerative cycle. While helping the Tzun, the Master used the alias Major Kreer. He was later shot by Ace which caused him to regenerate, however the Master managed to escape and retrieved his TARDIS by using a Stattenheim remote control, built from Tzun technology. After leaving a booby-trap for the Doctor in a nuclear warhead, the Master fleed. (NA: First Frontier)

The nanites the Tzun gave the Master eventually began to fail, causing him to seek the Loom of Rassilon's Mouse in order to make himself a new bod. The plan failed and the Master was taken away by UNIT soldiers. (NA: Happy Endings)