Absence - Employee vacation tracking system
Clean Email - Clean Email is an online service that empowers you to take control of your mailbox.
CWS TimeOut - CWS TimeOut is an online leave tracking software or absence management solution that can also be installed on the server.
MailClark - The Slack bot for external communications
PTO Ninja - Slack app helping teams better manage time off
Hiver - Manage Customer Support, Sales and Projects right from your Gmail inbox. Collaborate with Shared Labels, Shared Contacts, email notes, email reminders and email templates