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.
Balsamiq - Balsamiq. Rapid, effective and fun wireframing software.
draw.io - Online diagramming application
Invision - Prototyping and collaboration for design teams
Visio - Simplify and communicate complex information using data-linked diagrams.
Zeplin - Collaboration app for UI designers & frontend developers