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.

NAPS2 - NAPS2 is a document scanning application with a focus on simplicity and ease of use.

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

Simple Scan - Project information. Part of: The Gnome Project. Maintainer: Simple Scan Development Team. Driver: Simple Scan Development Team. Licence: GNU GPL v3.

PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request

XSane - A good proposal for SANE-2 has been written.