All regular Post Categories
get_categories( string|array $args = '' );
//returns Array of category objects. See get_terms() for possible $args for filtering returned category objects.
wp_list_categories(array|string $args = '');
//output categories as linked HTML to each category archive page. Can pass argument of echo=true to output directly.
All Terms in Taxonomy
get_terms( array(
'taxonomy' => 'post_tag',
'hide_empty' => false,
) );
//returns Array of category objects.
See possible parameters to get_terms().
No single function to get all terms as links. Example below to loop through get_terms() result with links.
<?php
$curr_term = get_query_var( 'term' ); //taxonomy term slug for page you are on
$terms = get_terms( array(
'taxonomy' => 'event-categories',
'hide_empty' => true,
'orderby' => 'name',
) );
foreach( $terms as $term ) :
$class = '';
if($term->slug == get_query_var( 'term' ) ) {
$class = 'current-cat'; //if is same as current term add class so can highlight it in list.
}?>
<li class="<?php echo $class; ?>"><a href="<?php echo get_term_link($term); ?>"><?php echo $term->name; ?></a></li>
<?php endforeach; ?>