Help me brainstorm: small gifts for repeat customers (retail)

I just got my first repeat customer today - woo hoo! My sales volume is growing slowly, which is okay. It gives me time to plan for future cool things and how to handle growth and stay organized. I've pondered the idea of including little freebies in my customer's orders before but haven't actually done it yet, and this first repeat order has me thinking about it again. I think it would be lovely to reward repeat business with a little gift, say around the 3rd or 5th order. (and more later, but it will take me while to grow to people placing more orders than that with me.)

But what would be nice gifts? I don't want them to be too self-serving, like discount coupons. And I want them to be appropriate to the customer. It would be dumb to send a little dog toy to someone who buys bird products, for example. Anybody here want to help me brainstorm?