FileConverter.digital - File Converter allows unlimited free conversions. Currently most commonly used to perform video conversions such as webm to gif, gif conversions.
Anvil PDF Filling API - The easiest way to programmatically populate any PDF
Magicul.io - Convert between Adobe XD, Figma, PDF, Illustrator, Sketch and more with 1 click
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
ConvertOnMac - ConvertOnMac is the best free online converter for every Mac user that supports more than 500 different file formats.
PlutoPDF - A URL to PDF converter wrapped behind a simple API.