Jigidi - Free online jigsaw puzzles. Hundreds of new jigsaw puzzles every day created by users from all around the world.
draw.io - Online diagramming application
Jigsaw Explorer - Premium online jigsaw puzzles.
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.
Jigsaw Planet - Free Online Jigsaw Puzzles
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.