Use stickers to make Spooky Candy Eyes also known as Royal icing transfers or candy decorations. They're helpful tools to use when decorating cookies.
Flowers that can be piped with buttercream or royal icing frosting (via Zimbio).
Christmas Royal Icing Transfers - The Bearfoot Baker
How to Store Royal Icing Transfers - The Bearfoot Baker; although this article tends to focus on mason jars, I think I would prefer the binder method shown at the end of the article
Free Printable Patterns and Tutorials for Hat and Mitten Royal Icing Transfers
How to Make a Royal Icing Primrose with a Step by Step Video via www.thebearfootbaker.com
How to Make Simple Royal Icing Roses Even if the Humidity is High