9. The Sycorax The Christmas Invasion (2005)
Other than blink and youll miss it background appearances in The End Of Time Part Two and The Pandorica Opens (which Im not counting for the purposes of this), the Sycorax have only been seen attempting to invade Earth in David Tennants debut story The Christmas Invasion. Theyre pretty much just your classic extraterrestrial empire builders. But what really elevates them above just that is their tribal culture, a way of life based on honour and conquest. Its not quite a unique selling point but it adds an interesting element to them. Theres a real sense of their culture instilled into The Christmas Invasion which is just crying out to be built on. Theyre a curious mix of the primitive and the advanced thats incredibly visually striking, particularly their Masai-inspired costumes. Theres scope for them to declare revenge on humanity since Prime Minister Harriet Jones destroyed the Sycorax ship that previously tried to invade Earth, or for an adventure set on their home planet that takes a look at how their society functions.