Hunter: The Vigil takes place in the same universe as X
- Supernatural: The Loyalists of Thule are Men of Letters (hence their focus on fighting Nazi zombies); the Winchester family and their friends are a cell of the Union or the Bear Lodge; Ghostfacers are involved in Network Zero.
- Small problem with the first one, Nazi zombies are not a focus enemy for the Men of Letter. They were an enemy, just like any other. It's the Juda Initiative that specifically fights the Nazi zombies.
- Buffy the Vampire Slayer: The Loyalists of Thule are the Watchers and the Chiron Group is the Initiative. Also, Maiden's Blood Sisterhood.
- Indiana Jones: Aegis Kai Doru is the Brotherhood of the Cruciform Sword.
- Hellsing: The Knights of St. George are the Hellsing Organization, the Malleus Maleficarum are the Iscariot.
- Friday the 13th: the telekinetic girl from Part VII was an undercover VASCU agent.
- The X-Files/Diogenes Club: VASCU, natch.
- TFV too with the Syndicate.
- Hellboy: Taskforce VALKYRIE is the BPRD. Big Red himself could have been a Lucifuge member if things had turned out differently.