I can't think of too many woman villians in slasher horror type films. there seemed to be more in Suspense thriller type films like Single wite female and The hand that rocks the cradle.

here are a few I can think of (some contain spoilers)

Shawnee Smith in the Saw movies

Susan Tyrrell played a creepy role in Nightwarning.

The Guardian had Jenny Seagrove who played Camilla a Druid who worshiped a tree.

Happy birthday to me

The Babysitter (1980)

The Initiation (1984) Daphne Zuniga played twins

Prom night II hello mary lou (1987)

April fools day (1986) the whole muffy buffy part was freaky

Urban Legend (1998)

Cheerleader Camp (1987)

can anyone think of others?












Spoiler:
Sleepaway camp was sort of female slasher role until the end