Draw.io

Make flowcharts, process diagrams, org charts, UML, ER and network diagrams

Description

Draw.io (formerly Diagramly) is a  free online diagram software. You can use it for making flowcharts, process diagrams, org charts, mind maps, wireframes, mockups, and network diagrams.

Its simple drag-and-drop interface is preloaded with all standard diagram shapes and connectors. You can save your work on Google Drive, Dropbox, OneDrive or your own device.

Price
FREE

Completely free :)