The First Incarnation William Hughes (Guest 2007) & James Dreyfus (Audio 2018)
James Dreyfus (2018)
Facts: Episodes: 1 Cause of Change: Unknown
First body, No regenerations used.
The "UNIT" Master Roger Delgado (1971-1973)
Facts: Episodes: 43 Cause of Change: Degeneration by the Time-Lords
Thirteenth body, all twelve regeneration used.
Peter Pratt (1976)
The Degenerated Master Peter Pratt (1976) & Geoffrey Beevers (1981)
Geoffrey Beevers (1981)
Facts: Episodes: 8 (4 with Pratt & 4 with Beevers) Cause of Change: Merges with Tremas' body
Thirteenth body, all twelve regeneration used.
The "Tremas" Master Anthony Ainley (1974-1981) (Guest: 1997(Game))
Facts: Episodes: 28 Cause of Change: Given a new Time-Lord body by the Tzun Fourteenth body, all twelve regeneration used.
The "Tzun" Master Only appeared in Novels
The Master had a high forehead, glossy moustache, neat beard, aristocratic nose and a lean face, and spoke in a rich cultured voice. He wore a Vandyke beard, a dark Italian-designed suit, a silk shirt, and a cravat with a silver bird-of-prey tiepin. - Source: Doctor Who Wiki
Facts: Stories: 2 Novels Cause of Change: Robbed of his Trakenite body by the Warp Core
Facts: Stories: 2 Audio-adventures Cause of Change: Supposedly stole a new body (not confirmed) Fifteenth body, all twelve regeneration used.
Picture not from Doctor Who
The Master Executed by the Daleks Gordon Tipple (Guest 1996)
Facts: Appeared in Tv Movie Cause of Change: Executed by the Daleks but survives by stealing a body from a human
Sixteenth body, all twelve regeneration used.
The "Bruce" Master Eric Roberts (1996)
Facts: Appeared in Tv Movie Cause of Change: Fell into the eye of Harmony but was resurrected into a dead human. Seventeenth body, all twelve regeneration used.
The Master stuck on Earth Only appeared in Comics
Facts: Stories: 2 Comic-stories Cause of Change: Unknown The Master switched bodies at least 3 times or more after this during his time on earth He was later given a new lease of life by the Time-Lords.
Eighteenth body, all twelve regeneration used.
The Reborn Master / "The Other Doctor" Alex Macqueen (Audio 2012-2016)
Facts: Stories: 6 Audio-adventures Cause of Change: Unknown
Twenty-second body, No regenerations used in the second cycle.
The War Master Only appeared in Comics
Facts: Stories: Unknown Cause of Change: A paradox caused his body to regenerate
Twenty-third body, one regeneration used in the second cycle.
The "Yana" Master Derek Jacobi (Guest 2007)
Facts: Episodes: 1 Cause of Change: Shot by assistent Chantho Twenty-fourth body, two regenerations used in the second cycle.
The "Harold Saxon" Master John Simm (2007-2009) (Guest: 2017)
Facts: Episodes: 7 Cause of Change: Stabbed in the back by his future self
Twenty-fifth body, three regenerations used in the second cycle.
Missy Michelle Gomez (2014-2017)
Facts: Episodes: 15 Cause of Death: Shot in the back by her previous self
Twenty-sixth body, four regenerations used in the second cycle.