This plugin is a filter for collapsing the subcategories from category list.
Adds a widget to display archive links using purely CSS-based collapsing.
Makes collapsing hierarchical pages/category/taxonomy lists: top level; ancestors, children, and/or siblings of current
This plugin creates a shortcode to add an expandable box to show and hide the selected content on a post or page with customisable show and hide links
Collabpsing Blogroll allows you to put your blogroll on a page or in a post. The categories can be collapsed.