Users (category)

auth_cookie_expiration

Allows you to change the lifetime of cookies used to authenticate users.

author_link

Allows you to change the URL of an author's archive page.

editable_roles

Allows you to change the list of site user roles requested by get_editable_roles().

map_meta_cap

Allows changing the primitive capabilities required when checking a user's permissions.

post_types_to_delete_with_user

Allows you to change the list of post types to delete when a user is deleted. This applies only to posts created by the user.

the_author_posts_link

Allows you to change the HTML of the link to the author's post archive page.

user_contactmethods

Allows you to change a user's additional contact information.

user_has_cap

Allows you to remove or add capabilities for an individual user.

user_register

Fires immediately after a new user has been registered on the site and the user data has been added to the database.

wp_login

Fires after a user has successfully logged in.

wp_new_user_notification_email

Allows you to change the contents of the email sent to a new user upon registration.