• https://github.com/maticzav/graphql-shield
• https://jkettmann.com/authorization-with-graphql-and-custom-directives
• https://jkettmann.com/3-ways-for-authorization-with-graphql-and-apollo
• https://www.apollographql.com/docs/apollo-server/security/authentication/

Also add common features like sending registration email etc. Following might be helpful:

• https://github.com/Volst/graphql-authentication