Adults Are Useless: Massively averted. Many of the teachers and staff are just as competent as the righteous heroes that make up the student body. Of course, this also means the people on the villainous side of things also know what they're doing.
Applied Phlebotinum: In spades. Healing magic and G-Diffusers and Neo Tanks and Phase Distorters, oh my. And that's not even mentioning the Phlebotinum that ends up in the food on occasion.
Bonus Material: The art and meme communities provide lots of this, in various forms: fanart, fanfiction, kink memes, surveys to be answered either in or out of character (although the former has no effect on game canon), and more.
Cross Over: Panfandom, but limited to video games.
"Freaky Friday" Flip: Woe betide those unfortunate enough to swap bodies thanks to the antics of a certain Skull Kid. Hilarity Ensues when the characters invariably pretend to be each other.
Humanity Ensues: A voluntary version (aside from the potential for a prank): Nonhuman characters are given the opportunity to become a human, which is referred to as either humanization or gijinka. There was even a seminar held once in a while to help those trying it for the first time, and there are different methods involved depending on what can be used (for example, Pokemon can learn it as a Hidden Move). However, this is not permanent, and a character can switch back and forth if they wish. A character doesn't even have to learn humanization to begin with if he or she (or the player) doesn't want to.
Journal Roleplay: Most interactions are done through this, although other methods of interaction aren't unheard of (such as an art-oriented thread on Tegaki E, or a chatroom or two-player chat on programs like AIM).
Mean Character, Nice Actor: A lot of characters are complete dicks. Their muns are usually the sweetest people you could ever meet.
Non-Player Character: There are quite a few of these, some major ones being Headmaster Hand, Crazy Hand, Tabuu, and Nancy the (cyborg) Cafeteria Ursaring. Some player characters have them in the form of pets or pokemon, for example.
Original Character: Characters that are based more around a species than a specific person (such as Pikmin or Pokemon) are pretty much fancharacters.
OC Stand In: Once in a while, someone decides to apply for a character that has very little importance, backstory, or even personality. And they succeed. Also, characters similar to the Heroic Mime can be subjected to a form of this.
Put on a Bus: Dropped characters almost always experience this. Some are reapped later on (by the same player or by someone else, and sometimes with a clean slate either way), but many are left with a Long Bus Trip. When Otacon was rebooted, he literally left on a bus.