PlatoForms - Convert PDFs to forms and let people fill them easily.
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
DeftPDF - An all-in-one free online PDF editor that does not require subscriptions or installations! DeftPDF is a free online tool that makes editing and converting easy in just a few clicks!
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.
Jotform PDF Editor - Automatically create polished, designed documents
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request