Textures.com - Textures.com is a website that offers digital pictures of all sorts of materials.
CONV. - Convert YouTube video to MP3, GIF or MP4
Poly Haven - Poly Haven (formerly known as Texture Haven) is an online website where you will find scanned textures without any cost and that are of high quality.
Softorino YouTube Converter - Download YouTube video & audio. Watch and listen offline
Poliigon - A library of materials, and HDR's for artists including free textures that want photorealism.
You-Get - Command-line utility to download media contents from the web