The Noun Project is the most comprehensive collection of icons in the world, and is available inside Book Creator for anyone with a paid subscription. Note, this feature is only available in Book Creator online, not in the iPad app.
Choose from over 2 million beautifully designed icons!
To add icons from the Noun Project:
Click + then Shapes
Use the search bar to find what you're looking for (you can type your search or use the Microphone to speak your search term).
Drag the icon onto the page or click on it to add it to your book
Use the Inspector (i) to change the colour, add a hyperlink or Alt text
Resize the image using the blue handles in each corner.
You can rotate the image using the green handle.
Note, whilst co-teachers can generally access all the admin features of a premium account, they won't be able to use Noun Projects if joining someone else's library, unless they have a premium subscription themselves.