Diagram from Marketta Kyttä's 2004 paper
Make your own Unicorn. http://www.alwayshobbies.com/crafts/fimo/craft-kits/fimo-unicorn-craft-kit
Rainbow Unicorn Guide - Paul Bradford Sugarcraft School by Celia from Bath Cake Company
UNICORN - would be super cute as a stuffed animal
Rainbow Birthday Party Mini Favor Bags by LittlePeanutEvents
Did something similar for the girls' birthday. Used rainbow streamers and white balloons and swagged them. Turned out cute!
You'll find lots of Fun & Free Printable Rainbow Decorations and Cards at www.amazing-kids-birthday-party-ideas.com/kids-party.html
DIY Rainbow Lollipop Holder. A great craft idea and DIY centerpiece to complete your rainbow party theme.:
Rainbow party favor bags. Adapting this for invitations.
Unicorn Party Supplies for your Unicorn Birthday Party from www.DiscountPartySupplies.com