Font Awesome is a web icon library created in 2012 in Boston, USA, offering 9000+ vector icons, with a free tier of 2000+ commercially usable icons and support for Web Font, SVG, and front-end components.
JSFiddle is an online code editor and sandbox for testing and sharing HTML/CSS/JavaScript code, supporting React, Tailwind, TypeScript, and more, usable without registration.
CodePen is a US-based (2012, Portland) online frontend code editor and developer community offering live HTML/CSS/JS preview, preprocessor support, and page hosting, serving as an inspiration library and prototyping tool for frontend developers.