One party idea that I wanted to do before was to have a custom rubber stamp made which we will use on balloons for my son's birthday party before. You can have a caricature made of your child's face and have these stamped on balloons and napkins. You can even have little ones made and use them for table numbers, dish name cards, loot bags, and other stationery you may use (invites, tags, thank you notes).
You can even have them made with positive or inspirational quotes or reminders and give as giveaways. I'm sure kids will love the unique souvenir and parents will likewise appreciate something cool and cute reminding their child to mind their manners, or brush their teeth, or that friends are to be treasured.