Chalk - Chalk is a calculator that tries to do right what others do wrong.
Snarl - Snarl is a notification system for Windows.
Public - Group chats.
Notifu - Notifu, a free open source pop-up balloon utility
Slaask - Slaask enables you to set up a dedicated live chat channel on your Slack.
Notify OSD - Canonicals on-screen-display notification agent, implementing the freedesktop.