draw.io - Online diagramming application
Prototypo - Streamlining font creation with open source typeface editor
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.
BitFontMaker2™ - Fast and easy Online Bitmap font Editor.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
FontForge - Free (libre) font editor for Windows, Mac OS X and GNU+Linux