replit - Code, create, andlearn together. Use our free, collaborative, in-browser IDE to code in 50+ languages — without spending a second on setup.
Flickr - image and video hosting website
JSFiddle - Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle code editor.
Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
CodePen - A front end web development playground.
ImageShack - Unlimited space to host images, easy to use image uploader, albums, photo hosting, sharing, dynamic image resizing on web and mobile.