JPEG to PDF - JPEG to PDF is a free program that can convert image files to PDFs.
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.
PDFill - Open, View, Edit, Save and Print PDF Documents without Adobe Acrobat
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
Convert-JPG-to-PDF.net - Convert JPG to PDF for free with this online service.
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request