Here are some of the open source projects I work on:
IdentityServer4 is a ASP.NET Core-hosted security token service (STS) to centralize authentication for applications. It supports OpenID Connect (OIDC) and OAuth2.
IdentityServer3 is a ASP.NET/Katana-hosted security token service (STS) to centralize authentication for applications. It supports OpenID Connect (OIDC), OAuth2 and WS-Federation.
IdentityManager a tool for developers and/or administrators to manage the identity information for users of their applications. This includes creating users, editing user information (passwords, email, claims, etc.) and deleting users.
MembershipReboot is a user account management library and is meant to provide a modern replacement for the built-in Membership library from ASP.NET.