Here's some various websites that work well on a Chromebook.
You can bookmark them, pin them to your dock, and have them run in a stand-alone window. They may not be "real" stand-alone applications, but they are close.
Note-taking
Evernote
Simplenote
Reading
Kindle Cloud Reader
File-sharing
MEGA
News and Weather
Weather Underground
Development
WiMi5
Music
Pandora
Spotify
Stitcher
Drawing
DeviantArt muro
Pixlr Editor
Sketchboard
Sketchpad
Chat
Google Hangouts
Facebook Messenger
Skype
WhatsApp
Fun
Droplets