I use OC's and canon characters sometimes. Which fandom interests you?
I'd be interested in Pokemon or The Hunger Games for original characters, and any of the Avatar series' for playing canon characters!
For Pokemon it could be travelling partners, or the rivals! Either could be pretty fun. Pokemon is a pretty solitary adventure with the rivals though, so it may be harder to get them together. For the Hunger Games it'd be fun to explore the Capitol or have it be people before and during the games.
I'd LOVE to play Asami for a LoK roleplay, and I really love Suki from the original series.