[Captain Nash]

Villains organization:

The "oh CRAP!!" level of villains (be they X-Men, general Marvel or Spider-Man) when you know when they show up it's all hitting the fan. They would only ally themselves with one another to serve their own ends and at extreme moments, and those moments are few and far between Some might not ally themselves with anyone, ever, period.

These include: Magneto, Apocalypse, Ultron, Kang, Thanos, Loki, Dr Doom, Galactus, Dark Phoenix and Red Skull.

Secondary are high threat villains but may still be manaage but luck and teamwork. They may be willing to make temporary alliances for mutal benefit:

Mandarin*, Mystique, Enchantress, Mister Sinister*, Iron Monger, Baron Zemo*, Leader, Green Goblin*, Dr. Octopus

* I would rank these four as slightly higher levels of threats than the others in the same group.
Third level are not necessarily the movers and shakers of the world but are still formidable threats, which at times can be taken out by either a very powerful (or lucky) hero, or a smaller team of heroes. They would be more likely to be followers than anyone of the above categories, which would only see each other as equals within their same levels.

This would include: Venom**, Bullseye**, Juggernaught, Sabretooth**, Omega Red, Klaw**, Grim Reaper**, Abomination, Blastaar**, The Wrecking Crew, Kraven, Hobgoblin, Absorbing Man, Mysterio,

** I'd rank these slightly higher than the others in the group.

I know there's others that have been made: Rhino, Constrictor, the upcoming Vulture, Silver Samauri, to name but a few. Those I'd put in the final category of lower level threats. Not anything to ignore but at the same time, they're not the highest of priorities to seek out unless they're actively causing problems. They are almost always followers.