re: #26 Kragar (Proud to be Kafir)
2 words, Vashta Nerada
Beat me to it.
However, in order of scariness:
1. Jamie 2. Vashta Nerada 3. Weeping Angels 4. The clockwork dudes from Girl in the Fireplace
(Daleks are somewhere down below the rhinoceros dudes, whose name I can’t remember.)