draw.io - Online diagramming application
Bulk Image Downloader - With Bulk Image Downloader you can download full sized images from almost any web gallery.
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.
Vov Picture Downloader - Download pictures from websites.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
Extreme Picture Finder - Extreme Picture Finder is a powerful batch image downloader.