I’m worldbuilding.

I always do, but occasionally I sit back and review.
It got me to thinking.
I write Paranormals, which means there are all manner of creatures running around.
In groups.
That requires a collective noun.
I’ve always been very fond of the term "A murder of crows", which got me to wondering…

What do you call a group of Vampires?
Here are some I found, I hope it’s a little helpful for some. :)

Vampires:

Coven, Clan, Pack, Kiss, Coterie.
(The place they inhabit tends to be called a Nest.)

Werewolves / Lycans / Werecats:

Pack

Demons:

Err… yeah. Not a clue. Still looking. Maybe "A Scare"?

Ghosts:

Haunt

Dragons:

Brood, Flight, Clutch

If I find any others, I’ll post them.
And if you have suggestions… put it in a comment. :)

Other words that describe groups of… anything, really, are:

Fraternity, Crew, Gang, Flock, Cluster, Herd, Family, Sect, Squad, Tribe, Legion, Cloud, Host, Swarm, Horde, Litter, Drove… the list goes on and on.
I’ve put up a page with collective nouns for people who are after the same thing. :)