Anvil PDF Filling API - The easiest way to programmatically populate any PDF
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
KDAN Mobile PDF Reader - PDF Reader is the one app you can rely on when you need a portable solution to work with PDFs.
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
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.
PlutoPDF - A URL to PDF converter wrapped behind a simple API.