The Sorcerer in my 13th Age game had a familiar for a while, a baby wyvern he named Thorn. Eventually he did some retraining and did away with the familiar talent, so he said Thorn got too old to be his familiar and flew away.
Now he plays it that, because his Sorcerer is aligned with white dragons, he can only use ice and lightning magic on his own ("thundersnow" storms, basically). Whenever he gathers power for a different breath spell, it's actually him summoning his wyvern, which divebombs with poison breath on the next turn. I think that's pretty cool.