The appearance of the renegade Ms. Post in the episode Revelations makes the Scoobies suspicious of new Watchers. This is reflected when Wesley enters their lives later in the season.

In Revelations, Xander notes that Buffy has been, “killing zombies and torching sewer monsters”. These are references to the episodes Dead Man’s Party and Band Candy.

In Revelations we hear ‘Silver Dollar’ by Lolly (Man of the Year) at the end of the episode.

In Revelations, Buffy says, “another Tuesday night in Sunnydale”, which is a reference to the fact that Buffy aired on Tuesdays in the U.S. In Once More, With Feeling, Buffy says, “So Dawn’s in trouble. Must be Tuesday”

Faith and Buffy fight and crash through a sheet of glass in Revelations. They do this two more times whilst fighting: in Graduation Day (Part 1) and This Year’s Girl.

Willow calls Giles, “The emotional marathon man” in Revelations. This is a reference to William Goldman’s character in his 1974 book. It was made into a movie in 1976 starring Dustin Hoffman.

A line of Faith’s about her motel room was cut from Revelations: “The decorator just left. Cost me a pretty penny - but a motif like this don’t come cheap.”

In a line cut for length from the episode Revelations, Cordelia proves she’s not convinced about the newly reformed Angel:
Cordelia: Okay, but when there’s a big massacre, who gets the I-told-you-so?”
Xander: “You get the I-told-you-so.”
Cordelia: “Just so we’re clear…”

We discovered in Revelations that there were twelve cemeteries in Sunnydale, including Restfield Cemetery and the Shady Hill Cemetery.

When the Scoobies approach Glory’s tower in The Gift, they look up, and Xander exclaims “Shpadoinkle!”. This is a reference to a line in Trey ‘South Park’ Parker’s movie Cannibal! The Musical. One of the first songs in the movie contains the verse ‘We think we know exactly what we …

In The Gift, Giles says, “We few… we happy few…” to which Spike replies, “We band ‘o buggered”, paraphrasing the famous “St. Crispin’s Day” speech in Shakespeare’s Henry V. The actual quote is, “We few, we happy few. We band of brothers.” In All the Way, Xander misquotes Henry V, …

In Selfless, Spike says, “Scream Montresor all you like, Pet.” This is from Edgar Allan Poe’s story The Cask of Amontillado in which Montresor bricks his enemy, Fortunato, up in his cellar, while still alive. Fortunato calls out to Montresor while he bricks him in, but Montresor carries on regardless. …

In Enemies, Buffy says about Faith, “The girl makes Godot look punctual”. This is a reference to a famous play by Irish author Samuel Beckett, Waiting for Godot, published in 1952.
During Primeval, Giles, Buffy, Willow and Xander meet at a crossroads after their falling out (in The Yoko Factor). They …

Tara’s father, Mr. Maclay, appeared in the episode Family. He was a domineering man who led all women in his family to believe they were half demon. Buffy and the other Scoobies stood up to him when he tried to take Tara away, and he was never seen again.

Mort was a huge vampire who was one of Harmony’s (dissatisfied) minions. He dislocated Anya’s shoulder and kidnapped Dawn in Real Me. He was staked by Buffy using a wooden unicorn horn. “Mort” is French for death.