enable filtering/searching by custom taxonomies in wordpress for visitors

I am new in wordpress.

How can I enable search/filter the contents/posts bye custom taxonomies as I created like ” SKU “, ” Metal ” etc. for visitors from frontend.

I have used ” tag-dropdown-widget ” plugin for searching by custom created taxonomies and used a drop-down search box in my page by following code:

if( function_exists( ‘taxonomy_dropdown_widget’ ) ) echo taxonomy_dropdown_widget( $args, $id );

But I want to search by more taxonomy type.

Please give me a suggestion what code or plugin I should to use.