Talking To Herself: In the 1999 series, Melissa Joan Hart (who played Sabrina in the 1996 live-action show) plays Hilda, and she also plays Zelda.
Zelda Spellman
Cool and Unusual Punishment: Due to abusing magic with Hilda, they have been turned into teenagers for 100 years. However, with Zelda, it's unknown why she'd be abusing magic as well.
Talking To Herself: She's also done by Melissa Joan Hart, who's also doing Hilda's voice in the 1999 series.
Uncle Quigley
Canon Foreigner: He only appears in the 1999 series. He was added in because with Hilda and Zelda as teenagers, there was no adult guardian living in the house.
Chuck Cunningham Syndrome: He disappears in Sabrina's Secret Life with no explanation. However, one could guess that he left because by then, Hilda and Zelda were legally adults at that point, and didn't serve a purpose anymore.
Canon Foreigner: She was created especially for the 1999 series. This could be because Viacom didn't want DiC to use any of the characters that only appeared in the 1996 live action show.
Trickster Mentor: He comes off as evil and scary but always left a loophole in whatever Sabrina wished for so she could find a way to fix it when it (inevitably) goes wrong. Though he's tired of constantly being asked.
Between My Legs: In "Nothin' Says Lovin' Like Somethin' from a Coven".
Canon Foreigner: Made especially for the 1999 series. Again with Viacom probably not wanting DiC to use Libby (DiC only used their characters and the characters already from the comics).
Give Geeks a Chance: Harvey isn't exactly the coolest guy around, yet Gem has an all too transparent crush on him. Though perhaps only to make Sabrina jealous.
Suspiciously Similar Substitute: For Gem in Sabrina's Secret Life. Surprisingly enough, she appeared as part of Gem's posse in an episode of the 1999 series, but unnamed and had no speaking roles.