Darla was Angels sire. She also was the masters favorite. Angel killed her to save Buffy.
The Master used Luke as his vessel to try and break free on his prison below Sunnydale. Buffy killed him stoping the Master from escaping.
The most powerful of all vampires is the Master. Trapped in a sort of dimensional prison, he was unable to enter our world, only able to act through his minions. With the help of these vampire followers, he was able to cross over to our world briefly by luring Buffy to his lair and biting her. Fortunately, Buffy wasn't dead and surprised the Master, impaling him. His minions, led by the Anointed One, tried to resurrect him using human sacrifice, but were foiled by Buffy, who then smashed the Master's bones to bits. The Master is gone forever, or at least for now.
A giant praying mantis, she has sex with virgin boys then bites off their heads.
Colin an eight year old boy vampire, who leads Buffy to her death at the hands of the Master.
The Three are warrior vampires who are very proud and very strong.
Imprisoned magically in an ancient book, Moloch is a demon fond of charming his victims into believing he is their friend, using them to do his bidding, then killing them. When the book was scanned into the Sunnydale High computer, Moloch escaped onto the internet.
Marc is a demon who needs human organs (brain-heart) every seven years to keep his human form.