PDFMate Free PDF Merger - PDFMate Free PDF Merger works as a PDF Joiner, PDF combiner, PDF breaker, image to PDF converter and PDF encryptor. With PDF Merger, you can batch merging pdf files, combining specified pages or converting scanned image file to create new PDF file.
Document .Net - Gives you API to do everything with a document in PDF, DOCX, DOC, RTF, HTML and Text formats.
PDF Joiner - This online tool allows you to join several PDF documents into a single file, free of charge.
PdfPig - Read and extract text and other content from PDFs in C# (port of PDFBox)
DocuPUB - DocuPUB is an online file converter, file merger, file compressor, and file resizing tool.
PDFSharp - Office & Productivity and Development