Below are list of some Filter hooks functions
1. has_filter()
2. add_filter()
3. apply_filters()
4. apply_filters_ref_array()
5. current_filter()
6. remove_filter()
7. remove_all_filters()
8. doing_filter()
Below are list of some Action hooks functions
1. has_action()
2. add_action()
3. do_action()
4. do_action_ref_array()
5. did_action()
6. remove_action()
7. remove_all_actions()
8. doing_action()
List some action and filter hooks functions in WordPress?