I've put together a table of 100 backgrounds for 13th Age. Most are examples from the Escalation Edition, but I've also added a fair amount myself. Yes, 13th Age emphasizes creativity and unique characters, but a list like this can get the creative juices flowing, and may function as a jumping-off point. Many of these are generic, but there's plenty of room for specialization.
And of course those who prefer an element of randomness in character generation can simply roll a d% to choose their backgrounds.