This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Proven Guilty
The results of the spiritual mauling of the fetches' and Molly's various victims, particularly one girl who was driven into a permanent state of catatonia. In Harry's own words, "She's not coming back."
Lloyd Slate's fate. He was a bastard, but nobody deserves that.
When Harry looks at a heroin addict with the Sight, her addiction manifests as green-black veins under her skin ending at dozens of tiny, hungry mouths opening and closing where her needle tracks were in the real world.
Murphy gets taken off the Splattercon!!! investigation as punishment for disappearing all day into the Nevernever, so she isn't on hand to spin things in a way that could exonerate Nelson. Considering he went crazy in the wake of Molly's mind-tampering and wandered away from the convention in a fit of paranoia, he probably doesn't have an alibi for the other attacks either, so may have wound up blamed for the murders as well as the theater-owner's beating.
At Molly's trial, the Merlin shows he is not a runner for the Reasonable Authority Figure he's been building himself up to be. When Harry finishes his speech and beat the Merlin at his own game, the Merlin moves to have Molly executed immediately, just to spite Harry. Thank God, literally, that The Cavalry showed up in time.
And even worse that that? Think about who this is. Just for a few moments. This is the Merlin, leader of the White Council, the closest thing to actual 'good guys' the Dresdenverse has to offer, at least on a large-scale. He's the wizard who later holds off the entire Red Court with a single, improvised ward. And he's the kind of guy who'll execute a young girl for trying to use black magic to HELP PEOPLE, when she couldn't have known better, during a War when he's in desperate need of soldiers, just to spite someone who really hasn't earned his ire, and has been doing everything in his power to stay the Hell away from him and his politics ever since. Yes, he started said War, but that's no reason to take it out on Molly. And he's the leader of the good guys.
This one is coming from the table top books, but Darby showing up, Molly's idea for using fear as motivating factor all from the same person Sandra Marling. And if you take some of the banter in the books as applicable to the books she disappeared with out a trace after Splattercon!!! They could have pulled an elaborate plan on Dresden and Molly that racked up a huge body count and manage to get out with Dresden noticing until he was writing down his case files and could have been working for anyone and are still out there.