As someone that wrote a book about Protection and Reversal Magick (as well as a secret un-published chapter that makes it a complete treatise called "Magickal Combat") I look into these types of groups a bit. The Process was relativly harmless, the ONA less so.
Here are a few more for your research:
Fraternal Order of the Golden Centurion: German Order founded in in 1840. Went underground in 1933. Still some rumors of their existence. Also known as the 99 Lodge because there were only 99 members at a time. Each year there would be a new member initiated, and if no one had died of natural causes that year, there would be a lottery for a sacrifice that was killed. Allegedly by Tepaphone.
The Sampwel, the Zobop, Bizango, and other Haitian Secret Societies: These are the folks that issue the passports, make the zombies and otherwise enforce Vodou law. Some see them as necessary in a lawless land. Some as thugs not much better than Ton Ton Macout, who were themselves a Secret Society.
The Dugma's: Not to be confused with Dugpas, who Blavatski claimed were the masters of all evil in Tibet, but are actually a major lineage within the Kagyu School. The Dugmas are a Tibetan cult of mostly women near the Tsangpo Gorge who feed poison to righ travelers. The travelers die days later and the Dugma believe that when they do, they steal their "merit". How's that for your overly simplistic view of the peaceful and enlightened Tibet?
Palero's: All the Palo's that I know are really quite nice and upstanding people. However, they are tapped into some forceful shit and tend to be, IMO, overly concerned with attacks and such. Because of their Ngangas and their work with human remains, in some cases fresh human remains, they often fall afoul of the law and thanks to Carlos Montenegro's rather sensationalistic book, they are get a worse reputation among occultsts than they deserve.
The Solar Lodge: Everyone in the OTO knows about Jean Brayton and the Solar Lodge. They know about the alleged connections to the Manson Family, and the infamous "Boy in the box" incident. Grady Mc Murtry wrote an article for an old OTO Newsletter claiming (let me see if I can remember this clearly) that members of the Solar Lodge were responsible for breaking to Sasha Germers house and among the items stolen was one of Crowley's books that conatined metal squares from Abramelin written in Enochian. He though perhaps this might have fallen into the hands of Manson. I will have to go to Thelesis and dig up the issue for the exact story, but they certainly are a boogieman.
I am sure I could think of more, but these come to mind.