My prefered tools is RoR on backend and React+Redux on frontend. Also I like to use webpack with postCSS and CSS-modules with LESS.
At Inventos I had participation in development apps for media. It was backend and frontend apps for TV1000Play and SmartTV app on Samsung Tizen and LG WebOS platforms. During development smartTV apps I built npm-package for navigation in smartTV apps with remote control. Now this package is available in open source.
At Statsbot I had participation in development BI tool (RoR, JS, React, Redux, D3 charts), additional microservices (Node.js), documentation portal (React, Gatsby.js) and marketing promo-sites (React, Next.js, LESS).