jPDFViewer - Use jPDFViewer Java PDF SDK to integrate a PDF reader right into your Java application or website.
Usersnap - Visual Feedback - Usersnap helps your business with its versatile feedback platform to build better, more successful products and services with the help of user feedback. Collect feedback along your product development lifecycle. Try it for free.
Wondershare PDFelement - All-in-one PDF editor
Tweakr.io - The fastest way to get visual feedback 📌
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.
Marvel - Turn sketches, mockups and designs into web, iPhone, iOS, Android and Apple Watch app prototypes.