Sketch - Professional digital design for Mac.
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.
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
draw.io - Online diagramming application
Affinity Designer - Professional creative software, exclusively for Mac.
yEd Graph Editor - yEd is a free desktop application to quickly create, import, edit, and automatically arrange diagrams. It runs on Windows, Mac OS X, and Unix/Linux.