Black Hat sometimes plays mini-golf to relax himself, along with reading the newspaper in his spare time. Notably, this was shown in a Description Cut when Flug thinks that Black Hat will commit some atrocity.
Also it's implied that he's a genius inventor and Gadgeteer Genius himself and made many atrocious devices only by himself and before Flug even existed.
He can play organ very well. And Word of God says he can play guitar very well too.
In Black Hat Challenge II he shows to be a great ventriloquist.
Dr. Flug
Dr. Flug appears to have some understanding of emotional states and self-esteem if his words to an imprisoned Miss Heed about how she needs to love herself first before seeking a romantic partner are anything to go by.
Demencia
While she is a crazy fangirl, videos like Demencia wuz here and Guide for an Evil Conquest show her to be as efficient as she is demented when it comes to evil activities, like stealing or killing heroes. It would explain why Black Hat keeps her around despite her annoying him so much. So scarily effective is she at combat in fact, that in "The Dreadful Dawn", where as Dr. Flug believed they'd need a special 30+ step plan in order to defeat the sun-powered Flying Brick hero Sunblast, Demencia scoffs at needing something as complex as his plan, and confidently proclaims that all they need to do is beat him up, and that she could do it by herself. This being Demencia, this just sounds like the suicidal boasting of a crazy person. But when Sunblast arrives, and she charges in with zero-planning beyond just getting into a slugging match with the hero, she actually has him on the ropes. Sunblast's disheveled and worn look, while Demencia looks barely bothered implies that if Flug hadn't been insistent on sticking to the plan, and the resulting botched tranq shot that followed, she would've made due on her claims, and beaten him singlehandedly. Flug learns from his mistake and lets Demencia go to town on Sunblast the second time they meet up by lying that Sunblast ships Black Hat and Penumbra.
(Q:"How many hatbots would I need to control the galaxy?") Dr. Flug's answer: Approximately 1.4 billion, 747 million, 56556e+22 Demncia's answer: 1,474,750,655,56e+22 5.0.5's answer: 2.note Which he was also correct with, if the galaxy is the size of a key-chain, according to Flug.
According to Satellite Secrets, she's learning French.
In The Heedeous Heart Demencia shows genuine concern for Flug and his welfare, implying she has genuine emotional depths that go beyond obsession.
Heroes
Bulldozer
Bulldozer flashbacks show he was an Elegant Classical Musician and can (or at least could) play harp very well.
Other Villains
Black Hot
He cares a lot about Black Hat's opinion on him and the only thing he truly wants is the approval of Black Hat.