PDFTK Builder - PDFTK Builder is a free graphical interface to for PDFTK, making it much easier to use.
UnityPDF - UnityPDF lets you merge, split, divide, rotate, protect PDF files and more.
QPDF - QPDF is a command-line program that does structural, content-preserving transformations on PDF...
PDFsam - PDFsam Basic, a free, open source, multi-platform software designed to split, merge, extract pages, mix and rotate PDF files
iSafePDF - iSafePDF is a free open source PDF protection software.
Clipperly - Convert, edit or optimize your files online. More than 400 different formats supported among documents, images, spreadsheets, ebooks, archives, presentations, audios and videos.