Here’s all the actions I’ve found so far to hook into (taken from Varnish plugin):
// When posts/pages are published, edited or deleted
add_action(‘edit_post’, array($this, ‘PurgePost’), 99);
add_action(‘transition_post_status’, array($this, ‘PurgePost’), 99, 3);
// When comments are made, edited or deleted
add_action(‘comment_post’, array($this, ‘PurgePost’),99);
add_action(‘edit_comment’, array($this, ‘PurgePost’),99);
add_action(‘trashed_comment’, array($this, ‘PurgePost’),99);
add_action(‘untrashed_comment’, array($this, ‘PurgePost’),99);
add_action(‘deleted_comment’, array($this, ‘PurgePost’),99);
// When posts or pages are deleted
add_action(‘deleted_post’, array($this, ‘PurgePost’), 99);
// When xmlRPC call is made
add_action(‘xmlrpc_call’, array($this, ‘PurgeAll’), 99);
// When a post changes from future to publish
add_action(‘future_to_publish’, array($this, ‘PurgePost’), 99);
// When Theme is changed
add_action(‘switch_theme’, array($this, ‘PurgeAll’), 99);