PDFsam - PDFsam Basic, a free, open source, multi-platform software designed to split, merge, extract pages, mix and rotate PDF files
PDFtk - PDFtk is a simple tool for doing everyday things with PDF documents.
PDFill - Open, View, Edit, Save and Print PDF Documents without Adobe Acrobat
AutoMetadata - AutoMetadata is a tool for exploring and manipulating metadata, document properties, and viewer preferences in multiple PDF documents.
UnityPDF - UnityPDF lets you merge, split, divide, rotate, protect PDF files and more.
Edit PDF metadata - Edit PDF metadata is an online tool from PDFCandy that can manipulate PDF info and metadata.