draw.io - Online diagramming application
15Five Plus - Insights to manage, measure, and retain great employees.
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.
Teambit - Teambit is a team engagement and performance platform, that makes feedback a daily habit.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
HappyTeam - The simplest way to keep a pulse on your team's mental health and well-being.