Some of these factions are fairly new and others have been around a while so quantities of background material varies significantly. I've therefore elected to start with the one that has the most material available for it...don't expect this much info on every faction though...
There are currently three other members of the Baker Street Irregulars though I don't have models for these so you'll have to make do with some artwork for now.
Mrs Hudson is a mysterious character equally capable of fitting in with the highest of high society or the lowliest of gangland thugs and making them feel jovially at ease. It is usually around this time that she will use her masterful grasp of poisons to do a serious mischief to her intended target... and sometimes those unfortunate enough to be in the vicinity too.
Sherlock's gang has recently acquired this mechanical marvel. Though nobody knows the full truth of where the brain that sits atop The Professor came from, many believe it once sat in the head of missing University Professor James Moriarty.
Every devious criminal mastermind needs a man on the force and though Holmes has many in his employ it is Crookes who, more than any, is willing to show his dubious allegiance, standing side-by-side with the Baker Street Irregulars in scuffles.