add_user_role
Action Hook: Fires immediately after the user has been given a new role.
Source: wp-includes/class-wp-user.php:564
remove_user_role
Action Hook: Fires immediately after a role as been removed from a user.
Source: wp-includes/class-wp-user.php:592
set_user_role
Action Hook: Fires after the user’s role has changed.
Source: wp-includes/class-wp-user.php:652
user_has_cap
Filter Hook: Dynamically filter a user’s capabilities.
Source: wp-includes/class-wp-user.php:810