Plumsail Documents - Document automation software that integrates with your favorite apps to generate documents seamlessly.
Okular - Okular is a universal document viewer based developed by KDE.
DocSpring - DocSpring provides a PDF filling API that makes it easy for programmers to fill out and generate PDF documents.
Sumatra PDF - Sumatra PDF is a slim PDF/DjVu/EPUB/XPS/CHM/CBR/CBZ/MOBI viewer for Windows.
WebMerge - WebMerge is an online platform that allows you to easily collect data, populate a document and send it to any contact automatically.
Foxit Reader - Foxit Reader is a free and light-weight multi-platform PDF document viewer.