Nowadays PMD RPs don't really last that long. Some didn't even take off like Yin and Yang., but that's probably because the GM wasn't there. There are some stories I know that might be able to be turned into an RP.
1. Star Wars
2. Avatar (The Last Airbender not Cameron's)
3. Charlie Bone series by Jenny Nimmo
4. Percy Jackson and the Olympians by Rick Riordan
5. 39 Clues series by tons of different authors
6. Superhero RPs (you know, iron man, green lanturn?!)
7. Harry Potter by you know who
8. Transformers
9. Armageddon or similar sci-fi doomsday movies
10. Maximum Ride series by James Patterson (i know it's done but it didn't go well)
11. The Kane Chronicles by Rick Riordan
12. Warriors series (you know. the cats. Seekers, the bears, works too)
13. Alex Rider series by Anthony Horowitz
and many more
Avatar has... Potential but the only way it would properly PROPERLY work was either if everyone was an avatar or nobody was. To have just the game master or a chosen member would just get out of hand. Also, if everyone is the avatar, it kind of would be subject to overpower in any situation thanks to the avatar state.
Charlie Bone is a great idea! I used to LOVE that series. Quirky powers are way better than the usual FIAR POWAR!!! I would join that, provided storyline went somewhere.
Percy Jackson would maybe work, it all depends which way you push it and what restrictions you put on it since people would pick favourites like ZEUS and POSIDON and such. Its just you'd either have to focus on that school shindig he went to or an adventure or somehow equalling out the two.
Superheroes ive already seen done here actually... Not that long ago! I think a superhero group origin story would be best though!
Harry potter is doomed for failure. Any school based rps, unless storyline is introduced STRAIGHT AWAY, it will die.
Alex rider is... Just a spy rp. Really. Teenage spies. We al know how those go :(
I'd like to see some where the age group extends way past the teen age.
Here, i'll lend some ideas:
Xam'd: Lost Memories. Although that would probably take far too long and die.
Assassin's Creed, anyone?
MISFITS!! i know i did it, but how about without the pokemon? d;
Anamorphs lololololololol ok
Or Heroes? Similar to misfits yeah.
....... Final fantasy? Well, more ivalice than anything. Yeah?
Silent hill? Fear factor is kind of lost over words though. d;
... BLUE EXORCIST!!
ok im done