The following hooks are available within Publisher's codebase which you can subscribe to and either alter data (depending on the hook), or perform additional actions when the hooks are called. For full context into the hooks it is best to search the Publisher codebase for instances of the hooks.
If you have an idea for a new hook please don't hesitate to reach out. Just provide an example of what the hook does and the benefit of adding it, and I'll consider adding it to the codebase.