This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / The Lizzie Bennet Diaries
If you read the book, Caroline's reaction to Lizzie's words here !
Caroline Lee in general. A manipulative, but apparently nice girl, who could, on a meta-level, turn a great part of a fandom's heads despite the Foregone Conclusion, because she looks clueless, charming and sweet. Paired with a Socially-Awkward Hero and an Horrible Judge of Character, one of which is her Unwitting Pawn and has a very shaky personal and financial situation she has interests in spoiling, on a vlog with tens of thousands of viewers, you get potentially the most damaging antagonist, if you exclude Wickham.
Wickham's increasingly uncomfortable leery manipulation of her, so much that Tumblr fandom blogs tag it under the trigger word of abuse so others can blacklist it.
This. Wickham is officially straddling the line between Jerkass and evil.
Georgiana "Gigi" Darcy is either a Emo Teen, either a Broken Bird. She is very young (possibly under 18), depressed for unknown reasons, describes herself as "the worst thing a girl can be, a beautiful little fool", and needs her overprotective brother's support. She has given up swimming recently. George Wickham is a villain. He is charming, manipulative and cruel. He is hated by "Gigi"'s overprotective brother for unknown reasons. He is a swimming teacher.
After episode 82, imagine the things that Gigi said to her brother's face, after she tells Lizzie that whatever Lizzie has said about Darcy doesn't come close.
In the Pemberley spin off with Gigi, she calls George after he disappears. We know he's scum. We've seen the proof in multiple videos. But when he claims that he didn't set up the website for Lydia's sex tape, it was stolen from him, he seems so sincere and convincing.