
yEd
draw.io
LucidChart
OmniGraffle
PlantUML
Dia
UMLGraph
Gliffy
kdiff3
Beyond Compare
WinMerge
Meld
Araxis Merge
DiffMerge
P4Merge
Devart Code Compare
yEd
kdiff3draw.io - Online diagramming application
Beyond Compare - Beyond Compare allows you to compare files and folders.
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.
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
OmniGraffle - OmniGraffle is for creating precise graphics like website wireframes, an electrical system designs, or mapping out software class.
Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.