Below are list of some Filter hooks functions :
* has_filter()
* add_filter()
* apply_filters()
* apply_filters_ref_array()
* current_filter()
* remove_filter()
* remove_all_filters()
* doing_filter()
Below are list of some Action hooks functions :
* has_action()
* add_action()
* do_action()
* do_action_ref_array()
* did_action()
* remove_action()
* remove_all_actions()
* doing_action()
