Okta - Enterprise-grade identity management for all your apps, users & devices
CAS - Apereo CAS - Enterprise Single Sign On for the Web
Auth0 - Auth0 is a program for people to get authentication and authorization services for their own business use.
OneLogin - On-demand SSO, directory integration, user provisioning and more
LoginRadius - Loginradius is a cloud-based customer identity and access management platform. LoginRadius empowers businesses to deliver a delightful customer experience without compromising security.
Atlassian Crowd - Crowd is a single sign-on and user identity solution.