Where can you find the available filter tags?

by

There are multiple was to find filters:

  1. Use an IDE (see Eclipse example), set WordPress as a separate project and search in this project for apply_filters or do_action.

  2. Get a program to search in all files of a directory (grep, Notepad++) and do the same search with that.

  3. Read the source code. If you start with wp_nav_menu() and follow the functions called in its definition you will find the filters and actions you need.