Rogue Trader: The Dark Project
The Dockmasters: The Enforcers and governors of the most important region of footfall: its docks. More an impromptu council of vaguely respectable individuals who do what they can to maintain order in the chaotic docking regions of the station.
The College: A secretive organization providing questionably legal housing and job finding aid to psykers from the Calixis sector and the Expanse alike. Though their legality is highly suspect, the College still provides the quickest and easiest way to find astropaths for employment to any rogue trader who might need them short notice.
The Red Schola: The largest slave market on Footfall, the Red Schola acquires its product from numerous places, none of which they will openly divulge. However, should a rogue trader be in desperate need of cheap manpower, impressive gladiators or champions, or just a place to deposite a large number of unwanted humans without spacing them, the Red Schola is likely the first place to go.
The Drusian Pilgrims: Every year thousands of Pilgrims trickle into the Koronus Expanse undertaking the dangerous Drusian Pilgrimage in which they attempt to follow the path of Saint Drusus in the final years of the Angevin Crusade. Though not a truly organized body, their shelters and hostels provide an excellent recruiting ground for faithful colonists as well as passengers, and their many anointed clerics are an effective means of connecting with the Ecclesiarchy back in Calixis.