Auth0 - Auth0 is a program for people to get authentication and authorization services for their own business use.
SaaS 1000 - Free exportable list of the fastest growing SaaS companies
Keycloak - Open Source Identity and Access Management for modern Applications and Services.
Look at that SaaS - Inspiration and resources for SaaS founders
Amazon Cognito - Amazon Cognito lets you add user sign-up, sign-in, and access control to your web and mobile apps quickly and easily. It scales to millions of users and supports sign-in with social identity providers and enterprise identity providers via SAML 2.0.
Inside SaaS Sales - 1000+ sales emails and voicemails from top SaaS companies