Sketch Repo - Collection of resources for anyone who uses Sketch
UX Flow Wireframe Prototyping System - Create beautiful user flows prototypes for your next project
SketchApp.rocks - Index of all awesome things related to Sketch.
draw.io - Online diagramming application
Flow - Stop managing projects from your inbox.
UMLGraph - UMLGraph is a professional automated drawing tool that allows the designers the declarative specification and drawing of UML class and sequence diagram.