After going through a lot of forums, I found out that there is no direct SAML ToolKit provided by Microsoft.

The Facebook, Google Authentication you are talking about uses a different protocol called OAuth/OpenID connect.

Most of the Identity providers have now moved to this standards but still people do choose SAML for conveniency. So in this cases you might need to write a solution on your own (which I won't recommend as it gets too complex and is a security concern).

You may opt for existing library solutions, You can choose any open-source or commercial solution like miniOrange, Sustainsys