GitHub Visualizer - Enter user/repo and see the project visually
pdflayer - Free, powerful HTML to PDF API supporting both URL and raw HTML conversion. Unlimited document size, lightning-fast and compatible PHP, Python, Ruby, etc.
Learn X in Y minutes - LearnXinYminutes isn’t a good way to learn your first programming language, but it’s a great way to...
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
Gource - Gource is a software version control visualization tool.
Tcpdf - TCPDF: Open Source PHP Class for generating PDF documents