Inbound Horizons

Simple Dropdown Filter by Category for Woocommerce automatically adds a dropdown on your shop catalog page that allows you to instantly filter products by WooCommerce product categories. The dropdown will show up on the shop page, product archive page and product tag page. It shows a product count per each category by default. The plugin currently supports only selecting a single category to filter.
The dropdown filter buttons shows up to the right of the native WooCommerce “sort by” dropdown and uses native WooCommerce component code.
<h4>Features and Extras</h4>
You can choose to manually exclude certain categories to show up in the dropdown filter if you do not want users to filter by those categories.
You can toggle off or on showing product counts by category or showing empty categories in your shop.
You can set custom CSS classes for styling the button to match your theme, and even apply custom CSS directly to the plugin from the back end settings panel.
It will work with nested parent/child categories you create in WooCommerce and display the child categories underneath the parent in your dropdown menu when users select a category.

Simple Dropdown Filter by Category for WooCommerce

Add a dropdown on the catalog page to filter products by WooCommerce categories.

Mark / t31os

Adds an additional dropdown menu to the post listing(also works for other post types that support post formats) to filter by post format.

Post Format Filter

Filter posts by post format, also supports custom types.

Simple Dropdown Filter by Category for WooCommerce vs Post Format Filter