Markdown by DaringFireball - Text-to-HTML conversion tool/syntax for web writers, by John Gruber
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
Characters - Characters makes it easy for writers, designers and developers to access special characters. They are easily found and copied to your clipboard, either as html code or as the character itself.
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.
Qwik - The HTML-first framework. Initialize apps of any size with < 1kb JS
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request