PDF24 PDF Creator - Create PDF and convert documents to PDF for free with the free PDF24 PDF Creator.
PDFTK Builder - PDFTK Builder is a free graphical interface to for PDFTK, making it much easier to use.
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.
QPDF - QPDF is a command-line program that does structural, content-preserving transformations on PDF...
PortableSigner - PortableSigner is a signing (with X.509 certificates) program for PDF files.
PDFsam - PDFsam Basic, a free, open source, multi-platform software designed to split, merge, extract pages, mix and rotate PDF files