See my colleague Laura Ennis's Apps Libguide for lots of ideas. The App of the Week offers a closer look at selected products.
Here are some other gadgets that might aid with creativity - I haven't tried all of these, but I hope they would be fun to explore.
Yutonga: ongrowing ideas- "By using the ideation process of yutongo you can solve any creative problem as finding a name, coming up with a s smart product or service idea or even finding an intelligent solution for complex technical problems"
Crayon - Create your own newspaper. "CRAYON is a tool for managing news sources on the Internet and the World Wide Web. The result is a news page customized for you with the daily information that you are most interested in."
ToonDoo - world's fastest way to create cartoons.
MindTools - toolkit containing more than 700 management, career and thinking skills. Includes a section on Creativity. Not everything is free.
PowToon - create animated videos and presentations
Infogr.am - create interactive infographics
TED: Ideas worth spreading - "Riveting talks by remarkable people, free to the world"