Edward Waterfield and Theodore Maxtible were human scientists who experimented with time travel, bringing them into contact with the Daleks in 1866. (TV: The Evil of the Daleks)
Fyodor Nikolai Kerensky was a scientist working for Count Scarlioni in 1979. He was killed by the Count when he was no longer useful. (TV: City of Death)
Soldeed was the last surviving scientist and de facto leader of the planet Skonnos. He arranged a deal with the Nimon so Skonnos could conquer the galaxy. When he discovered the Nimon would not honor their agreement, he could not believe it. He was killed by Seth. (TV: The Horns of Nimon)
Dalek scientists were members of the Temporal Research Team and the Dalek Scientific Division. (PROSE: Prisoner of the Daleks, AUDIO: The Genocide Machine, Return of the Daleks)
A scientist had created the Umbra, and brought destruction to his home planet. (COMIC: The Eye of Torment)