I name every single one that we keep. There is one named 23, but that's because we decided late that we were going to keep him, and we got REALLY used to calling him 23...so it stuck. lol
To amuse ourselves, most of our snakes are named after deities (like Aten and Persephone). Some are named after fictional characters. It's easier to keep track of them with names than it would be with just numbers or codes.