Jitsi Meet

Jitsi Meet is a fully open-source video conferencing solution that can be used for free via its public servers or self-hosted for complete control and privacy. It supports large meetings (scalability depends on self-hosted infrastructure) and offers features like end-to-end encryption, live streaming, and collaborative document editing. Its key advantage is the absence of mandatory accounts, downloads, or vendor lock-in. For large tech-savvy teams or organizations with strict data sovereignty requirements, self-hosting Jitsi provides a customizable, secure alternative.

It scores highly for its unparalleled privacy control, $0 cost for the core software, and active developer community, though it requires technical expertise for deployment.