Open Source Facial Recognition
A face is a password you can't change, which makes face recognition the one kind of data where a single leak is permanent - and where the line between a convenience and a liability is whether the templates ever leave your control. The open source options here run detection, matching, and face login on infrastructure you own, so the biometric data and the embeddings derived from it stay inside your perimeter rather than uploaded to a service whose breach would expose something nobody can ever reset.

InsightFace
Open source 2D and 3D face analysis toolbox with local evaluation, recognition, detection, and face swap trials

DeepFace
Lightweight Python face recognition and facial attribute analysis with multiple model and detector choices

CompreFace
Open-source facial recognition service with REST API and Docker deployment
Howdy
Windows Hello style facial authentication for Linux using an IR camera and PAM