PDFCreator - PDFCreator converts every printable document to PDF and many other formats. Create professional PDFs with a few clicks and it's free. With many Professional Features: merge documents, send emails and more.
draw.io - Online diagramming application
Foxit PhantomPDF - Edit PDF files with our feature-rich PDF Editor. Download Foxit PDF Editor to convert, sign, scan / OCR & more. A speedy PDF Editor alternative to Adobe Acrobat.
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.
bioPDF - PDF Writer - Create PDF documents from any Windows application - Supports Citrix MetaFrame, Windows Terminal Server and Windows 10, 8, 7, Vista, XP, Server 2019, 2016, 2012, 2008, 2008 R2, 2003, 2000. Works with 32 and 64 bit systems.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.