ApproveIt for Slack - Get approvals in minutes, not days. Right from Slack!
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
RemoteTeam - Remoteteam.com helps remote teams become great places to work with the fully-integrated platform to automates payments and HR tasks.
draw.io - Online diagramming application
Swipes - Plan projects, take action and discuss.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.