Sticky Note Boards
Padlet
Lino.it
Great guide for using Lino.it from Librarian's Quest.
Corkulous - iPad App

Mind Mapping
Popplet
Bubbl.us

Connecting
Twitter
Goodreads

Publishing
Book Creator (Android, iOS)
LucidPress
Blogs (Kidblog, Blogger)
Google Drive

Video
Jing
Snagit (Chrome Extension)
YouTube
WeVideo
Explain Everything (Android, iOS)
Educreations

Audio
Vocaroo
AudioBoom (Android, iOS)
TwistedWave

Other Tools
Google TourBuilder (does not work with Chromebooks)
Google Views
QR Codes (Creator, Reader)
Wordle