Propose new ZP merchandise or review the goods you've ordered.
I love all the little extras you add when you send out your items from the shop. Just a thought but maybe you could include a special pattern for people when they order from the shop next year. Maybe even 3 or 4 different ones and no one really knows what they'll get. Even if they are just variations on older patterns like ash with a chainsaw or something like that. Might entice people to order to get that extra special pattern.
I was going to say hat this had done before a few years ago. Ordered a couple of tees and a pattern arrived. I have been secretly carving that David Bowie pattern every year since........only joking. It was a pattern that was released a few weeks later but it was a great suprise.