Just thought I would start a topic regarding character meets at Universal and which of those you meet you can request signatures from. Many people may not know that this is a possibility due to the slightly more 'adult' nature of universal.
Much like the character meets at Disney, many of the characters will sign books etc if requested. Although not all are able to sign due to costumes may of these ones however can provide stamps or stickers for 'meet and greet' books instead.
I'll try to create and maintain a bit of a list below.
Feel free to comment and let me know any that you'd like to add or know about
I'll update this with the people we saw soon once I go home and get the signature book out