Grand Unifying Guesses/Monster Hunters Union

The following Occult Detective and Urban Fantasy series take place in the same universe, and their respective monster slayers are all members of a Monster Hunters' Union:

 * Blade
 * Bleach
 * Buffy the Vampire Slayer and Angel
 * Good Omens
 * Hellboy
 * Hellsing
 * Monstrumologist
 * Moonlight
 * Sanctuary
 * Special Unit Two
 * Supernatural
 * Witchblade
 * Wolf Lake
 * The World of Darkness
 * The Dresden Files
 * John Dies At the End
 * Anita Blake
 * Van Helsing
 * The Lost Boys
 * Kolchak the Night Stalker
 * The Monster Squad
 * Ghostbusters
 * Scooby Doo and his friends are junior members.