This is the last one I have, that hasn't been posted
Vladislav Roslyakov is another shooter of note - he tried to recreate the Columbine massacre by himself - he wore similar clothes, tried a similar plan if i remember correctly, etc. He ended up braining himself in the library, and photos of the body had him posed pretty close to Eric Harris' corpse, if I recall. The guy was a big fan, it seems. There are some webbums out there, detailing the attempt.

Randy Stair is the one who thought he'd become a ghost girl with no butthole, after his shooting, and there's a lot of embarrassing footage prior to him committing the act out there, that has been given meme remixes.