Ash Ketchum really loves Pokemon, because who wouldn't? And Pokemon seem to love him back, too. It's given him a bit of a skewed perspective on what counts as rare, though...
Twilight Sparkle has been here before. In fact, she's been here so often she's thoroughly bored. Time Loop stories for Equestria.
There's a Lothwolf. He's a Jedi. Why not, after all?
Harry Potter is a dragon. He's been a dragon for several years, and frankly he's quite used to the idea - after all, in his experience nobody ever comments about it, so presumably it's just what happens sometimes. Magic, though, THAT is something entirely new. Comedy fic, leading on from the consequenes of one... admittedly quite large... change.