The Trygon Factor was created in 1966.
The scientific name for the stingray is Dasyatis pastinaca, also known as Trygon pastinaca. It is a cartilaginous fish characterized by its flattened body and whip-like tail with a venomous stinger.
The 'Human' Factor was created in 1975.
The Zoya Factor was created in 2008.
The Ascension Factor was created in 1988.
The Fizz Factor was created in 2002.
The Dreadnaught Factor was created in 1983.
The Alien Factor was created in 1976.
The XY Factor was created in 2002.
Factor T was created in 1956.
The Dalek Factor was created in 2004.
The Radio Factor was created in 2002.
Critical Factor was created in 1953.