Listen I just love Danny who is unnaturally good at the most seemingly random hobbies/jobs thanks to his ghost powers. The kind of thing where you wonder why he would even be doing such a thing in the first place, but he does it so strangely perfectly that you're left wondering why you ever doubted. It only adds to the mystery that is Danny Fenton.
Obviously the cheer AU is part of this, but there are so many other possibilities. I know I've seen people talking about him learning magic tricks and illusions and being terrifyingly good at it.
He gets roped into doing a stint as a stage hand during the spring play (bc detention doesn't work as a punishment, so Lancer has the idea of giving him "community service". It works better than expected, and Danny finds himself enjoying it). All the theater kids can talk about is how good he is at moving things silently, how he can creep about without being seen at all, how he can help set off some really dazzling special effects.
People on his block start to pay him to get into their crawl spaces for various reasons, because he manages to get in and out and maneuver about way better and faster than an actual professional.
All the athletes in the school start to wonder how he got so good at identifying injuries and helping remedy them, but he's just so fast and precise that they don't complain. More than one person jokes about how he should become a trainer.
After witnessing his tactical prowess during the events of "Pirate Radio," students start coming up to him to help them develop strategies for sports plays or debates or, in one case, a tabletop RPG campaign. He's not as good at figuring it out beforehand as he is at figuring it out in the heat of the moment, but that doesn't stop people. Dash can be seen more than once at the very edge of the sideline, asking him about certain plays.
Feel free to add on more ideas if you have them. I just love things that only add to the mystery that is Danny Fenton.