6 classes are annotated with Oauth2Grant in Simple OAuth (OAuth2) & OpenID Connect 8.2

AuthorizationCode in simple_oauth_extras/src/Plugin/Oauth2Grant/AuthorizationCode.php

Plugin annotation @Oauth2Grant( id = "authorization_code", label = @Translation("Authorization Code") )

ClientCredentials in simple_oauth_extras/src/Plugin/Oauth2Grant/ClientCredentials.php

Plugin annotation @Oauth2Grant( id = "client_credentials", label = @Translation("Client Credentials") )

Code in simple_oauth_extras/src/Plugin/Oauth2Grant/Code.php

Plugin annotation @Oauth2Grant( id = "code", label = @Translation("Code") )

Implicit in simple_oauth_extras/src/Plugin/Oauth2Grant/Implicit.php

Plugin annotation @Oauth2Grant( id = "implicit", label = @Translation("Implicit") )

Password in src/Plugin/Oauth2Grant/Password.php

Plugin annotation @Oauth2Grant( id = "password", label = @Translation("Password") )

RefreshToken in simple_oauth_extras/src/Plugin/Oauth2Grant/RefreshToken.php

Plugin annotation @Oauth2Grant( id = "refresh_token", label = @Translation("Refresh Token") )