PacketFence - PacketFence is a Free and Open Source network access control (NAC) system.
Fing - Discover which devices are connected to any Wi-Fi network, map devices, detect intruders, assess...
FreeRadius - FreeRADIUS is responsible for authenticating one third of all users on the Internet.
Okta - Enterprise-grade identity management for all your apps, users & devices
Keycloak - Open Source Identity and Access Management for modern Applications and Services.
Auth0 - Auth0 is a program for people to get authentication and authorization services for their own business use.