pdflayer - Free, powerful HTML to PDF API supporting both URL and raw HTML conversion. Unlimited document size, lightning-fast and compatible PHP, Python, Ruby, etc.
PDFTK Builder - PDFTK Builder is a free graphical interface to for PDFTK, making it much easier to use.
Doczilla - Effortlessly create stunning PDFs and screenshots. Seamlessly store them in your own AWS or Google Cloud Storage bucket, putting the control and creativity right at your fingertips.
QPDF - QPDF is a command-line program that does structural, content-preserving transformations on PDF...
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.
PyPDF2 - PyPDF2 - A utility to read and write pdfs with Python