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.
Probably the Trygon/Mawloc, these tower above any other Tyranid in your army.
The Dalek Factor was created in 2004.
The Radio Factor was created in 2002.
Critical Factor was created in 1953.
The It Factor was created on 2002-01-06.
The Zoya Factor was created in 2008.
The Fizz Factor was created in 2002.
The Ascension Factor was created in 1988.
Factor T was created in 1956.
Welsh Factor was created in 2007.