Sontar (The Infinity Doctors)

General Sontar was the ruler of the Sontarans. He was said to look older than other Sontarans and was important enough to share the name of his people's home planet Sontar. (PDA: The Infinity Doctors)

He masterminded the two thousand year war against the Isari.

It does not seem unreasonable to speculate that Sontar was the genetic template from which the entire Sontaran race is cloned. This would make sense if Sontar looked older than every other Sontaran, as he would have come first.

Possibly Apocryphal Information
There is an account of a Sontaran known as Sontar trapped in an Egyptian Pyramid; it is unclear if this is the Sontar or another individual known by that name. (DWM: The Gods Walk Among Us)

Behind the Scenes
The suggestion that the Sontarans derive their name from a single person originated from the FASA Doctor Who Role Playing Game which claims that they named their planet after him.