Here is a list of all templates used by b2evolution v5:

_email_footer.inc.*.php

This is included into every email to provide footer text, including a quick unsubscribe link.

_email_header.inc.*.php

This is included into every email and typically includes the site name/logo as well as a personalized greeting.

account_activate.*.php

This is sent to a User when he needs to activate his account. Typically includes an activation link.

account_activated.*.php

This is sent to System Admins to notify them that a new User account has been activated. (This happens after registration).

account_closed.*.php

This is sent to System Admins to notify them that a User account has been closed (either by the User themselves or by another Admin).

account_new.*.php

This is sent to System Admins to notify them that a new User account has been created. (This happens before activation).

account_password_reset.*.php

This is sent to a User when he requested a password reset. Typically includes an link to access the password reset/change screen.

account_reported.*.php

This is sent to System Admins to notify them that a User account has been reported by another user.

comment_new.*.php

This is sent to Users and/or Moderators to notify them that a new comment has been posted.

comments_unmoderated_reminder.*.php

This is sent to Moderators to remind them that some comments are still awaiting moderation 24 hours after they have been posted.

contact_message_new.*.php

This is sent to a User or Blog Owner when someone sends them a message through a contact form (which is called from a comment, footer of blog, etc.)

post_new.*.php

This is sent to Users and/or Moderators to notify them that a new post has been posted.

private_message_new.*.php

This is sent to a User to notify them when someone sends them a private message on the site.

private_messages_unread_reminder.*.php

This is sent to a User to notify them when they have had private messages waiting to be read on the site for several days.

scheduled_task_error_report.*.php

This is sent to System Admins to notify them that one or more Scheduled Tasks failed to execute properly.