remm

This plugin provide widget that display a list with categories and posts in your sidebar. 
Widget can save the opened categories, and use cache.

Wp Ajax Tree

This plugin provide a widget that display a category and pages tree on your sidebar, using ajax to collapse categories.

Morteza Geransayeh

This plugin create dynamic expand/collapse tree-widget navigation from wordpress nav menu. When plugin activated, go to widgets page and drag the widget to theme widgets area and choose menu from the list and that’s all! 
Plugin has a basic-light theme. Yous can create special and bueaty theme (linke top banner screenshot) by yourself. RTL style included in plugin css folder.

WP-Parsi navigation trees

پیشنهاد میکنم از این پلاگین استفاده کنید

This plugin create dynamic expand/collapse tree-widget navigation from wordpress nav menu.

Wp Ajax Tree vs WP-Parsi navigation trees