Name...

I'm 32 weeks with my son. Who I love. But when we settled on his name, I thought we were having a girl. So I didn't put much thought into his name. (Don't do this ladies!) Anyway, his name is Robert Mitchell Surname. Everyone calls him Robby though. And he's Robby to me. But is there any other name that I could use the nickname Robby for? I know there is Robinson, but I'm not too keen on that..