iSafePDF - iSafePDF is a free open source PDF protection software.
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
PDF Unshare - pdf unshare, pdf protection, protect, share, updf, prevent, Lock PDF, Encrypt PDF, PDF Access, Lock, PDF, Encrypt, Access
DocRaptor - As the only API powered by the Prince HTML-to-PDF engine, DocRaptor provides the best support for complex PDFs with powerful support for headers, page breaks, page numbers, flexbox, watermarks, accessible PDFs, and much more
PDFTK Builder - PDFTK Builder is a free graphical interface to for PDFTK, making it much easier to use.
PDFCrowd - Pdfcrowd is a Web/HTML to PDF online service. Convert HTML to PDF online in the browser or in your PHP, Python, Ruby, .NET, Java apps via the REST API.