Glimmer - Fast and light-weight UI components for the web
Skype for Slack - Move your slack discussions to a group skype call
Preact.js - Preact is a fast 3kB alternative to React with the same modern API. Components & Virtual DOM.
Aircall Now - Make voice calls inside Intercom Messenger 📞💬
Svelte - Cybernetically enhanced web apps
Calls on Slack - Make voice calls in Slack