Usurian

The Usurians were manipulative life forms native to the planet Usurius.

Biology
The Usurians didn't need to breathe and looked like a small handful of green kelp in their natural form, although they belonged to the fungus, not vegetable kingdom. They could assume the shape of a dwarfish humanoid as long as they constantly exposed themselves to particle radiation. They were listed in Professor Thripsted's Flora and Fauna of the Universe as poisonous fungi. (DW: The Sun Makers)

History
Though they were originally a war-like race, this was inefficient and so they turned to commerce, creating the Company. Apparently very knowledgeable, their databases contained information on Gallifrey (which they did not consider a viable market for their consumer products) and knew of the Doctor's previous acts of "economic subversion".

The Company moved the Humans of Earth to Mars after Earth became uninhabitable due to pollution. The Humans were nearly taxed to death. When Mars also became uninhabitable, they moved the humans to the city of Megropolis 3 on Pluto and set up six artificial suns. They drugged the humans with sedatives, exploited them and ruthlessly taxed them, under the leadership of the Collector. (DW: The Sun Makers)

Other references

 * Legion had encountered the Usurian before and noted their obsession with business. (NA: Lucifer Rising)
 * The Veltrochni also knew of the Usurians and their obession with profits. (NA: The Dark Path)