PlutoPDF - A URL to PDF converter wrapped behind a simple API.
Softorino YouTube Converter - Download YouTube video & audio. Watch and listen offline
Pdf.to - Convert PDF to Word, Excel, JPG, & from. Also compress PDF
Yout - YouTube to Mp3 Converter
ConvertOnMac - ConvertOnMac is the best free online converter for every Mac user that supports more than 500 different file formats.
You-Get - Command-line utility to download media contents from the web