Yeah I don't think there is any explicit ones. And I could see this as a problem when you're in a ton of games (I'm not so I've never considered searching my games period). One workaround would be to tag the games you're a DM in with a keyword since you can search by tags. Though, I don't know if you can tag games you didn't create. I'm not part of any games I didn't create, so I can't check that.