Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
RxDB - A fast, offline-first, reactive Database for JavaScript Applications
Supabase - An open source Firebase alternative
SignalDB - reactive local javascript database
RemoteStorage - An open protocol for per-user storage OWN YOUR DATA
PouchDB - Open-source JavaScript database inspired by Apache CouchDB that's designed to run well within the browser