Members:
Abe Sapien
Ben Daimio
Hellbaby
Hellboy
Johann Kraus
Liz Sherman
Roger

Power: B.P.R.D.
This monster gets +1 to its attack value for every friendly member of its cabal adjacent to the target.

Members:
Bloody Tom V
Candy Striper V
Gerard V
Razorvixen V
Stoker
Vampire Enforcer V

Power: Feed
At the beginning of your turn, as a free action you may deal 2 unpreventable damage to a friendly cabal member adjacent to this monster to heal this monster of 1 damage.

Members:
Asylum Spirit V
Carousel Ghost
Executed Convict E
Headless Horseman
Skeletal Maiden V
Snuggles V

Power: Vengeance
This monster's controller gets an extra action each turn, which can be assigned only to a friendly member of this monster's cabal.

Let’s take a look at the cabal power:

Cabal Power: Vengeance - This monsters controller gets an extra action each turn, which can be assigned only to a friendly member of this monster's cabal.

A very powerful power indeed. To use this power you need, of course, the cabal leader. In this case that is the Headless Horseman. For someone who lost his head, he has a nice dial, and add 2 to the number of plot twists in your crypt. Movement is often underappreciated, but it is one of this monster’s strongest facets.

There are other monsters with the cabal power: the V Skeletal Maiden and the E Executed Convict from the base set, and the V Asylum Spirit from The Lab. The V Skeletal Maiden is possibly the worst monster from the base set. You can’t transform on the first click. You can move and slay a victim, but you won’t transform. Next turn, you could, but it becomes really dangerous if your opponent runs slay prevention. And, if you manage to transform, you get an 8 attack with a matching lousy defense of 14. So it is better to leave the Skeletal Maiden where she is, and look at the other two. The Executed Convict works better. The first two clicks can be used to get a good position using Ghost, while slaying a victim in the mean time. On the third click our culprit is ready for battle. A nice 10 attack, 3 damage and invulnerability should make sure he can at least hurt your opponent. If we look at the Asylum Spirit, he has the very useful Possession ability to get around in the madhouse. Too bad he’s not that much better than his rookie or experienced counterparts.

With this said, I think a team with just monsters who have the Furies-cabal is far from competitive. You could use Headless Horseman, V Asylum Spirit and E Executed Convict in a 200 point team. But with just 3 monsters, the third action you get from the cabal is a bit useless. When the cabal power shines, though, is if you use the Headless Horseman and 3 cheaper figures in a 200 point team. You have enough monsters to assign actions to, and 3 actions a turn gives you a lot more flexibility. With 300 points, you could use the Headless Horseman and either the E Executed Convict or the V Asylum Spirit, and use the remaining 145 for some cheap but powerful pieces (RE Asylum Spirit are great if you want to keep it thematic).

Ratings:

Furies cabal power: 4/5

Headless Horseman: 3/5

V Skeletal Maiden: 1/5

E Executed Convict: 4/5

V Asylum Spirit: 3/5

Members:
Freddy Krueger
Freddy vs. Jason
Hearteater
Jack In The Box
Jason vs. Freddy
Morgana
Rasputin
Satanist
The Black Death
Tunnel Terror
Yama

Power: Banish
All friendly monsters of this cabal get +1 to their attack values against Hellspawn and Spirits.
Sequel
When this monster would be eliminated, roll a D6. On a result of 5 or 6, it is not eliminated. Instead heal it of damage equal to the dice roll.

Members:
Avatar of Cthulhu
Brine Witch V
Deep One R
Shoggoth

Powers: Dark Gift
Each time a friendly monster of the cabal kills a monster, heal another friendly member of the cabal of 1 damage. Madness
When this monster, or a friendly member of this monster's cabal gets an attack roll result of 11 or 12, the target becomes insane.

Members:
Archangel
Bailey and Jameson V
Big Red
Bishop Luzifer
Butcher
Faith Priest V
Field Agent R
Officer Friendly V
Santa
Tracker Voodoo Priest

Powers: Exorcism
When a friendly member of this cabal rolls a critical hit agains a Spirit, kill the Spirit instead of dealing damage to it. Correction
This monster and all friendly memebrs of this monster's cabal modify their attack values by +1 against Killers and Slashers.

Members:
Dire Werewolf
Dire Wolf R
Dire Wolf V
Dog Soldier V
Werewolf Leader
Werewolf Orderly V

Powers: Pack Tactics
This monster gets +1 to its attack value for every friendly member of its cabal adjacent to the target.
Alpha Male
This monster and all friendly members of this monster's cabal modify their attack values by +1 for each friendly member of their cabal adjacent to the target.