Bulma - Bulma is an open source CSS framework based on Flexbox and built with Sass. It's 100% responsive, fully modular, and available for free.
Zoom - Equip your team with tools designed to collaborate, connect, and engage with teammates and customers, no matter where you’re located, all in one platform.
Material UI - A CSS Framework and a Set of React Components that Implement Google's Material Design
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Milligram - A minimalist CSS framework
WhatsApp - WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.