Gargron

This widget shows all tags that are anime titles as a dropdown menu. It creates a taxonomy called Anime, you only need to tag your posts not in the ‘Post Tags’ box, but the ‘Anime’ box.

Anime Dropdown Widget

This widget shows all tags that are anime titles as a dropdown menu. Using WordPress' custom taxonomies.

Erick Hitter

Creates lists of non-hierarchical taxonomies (such as <code>post tags</code>) as an alternative to term (tag) clouds. Multiple widgets can be used, each with its own set of options.
Numerous formatting options are provided, including maximum numbers of terms, term order, truncating of term names, and more. List styles are fully customizable, with built-in support for bulleted lists and numbered lists.
Using the <code>taxonomy_list_widget</code> function, users can generate lists for use outside of the included widget.
Only use version 1.2 or higher with WordPress 4.2 and later releases. WordPress 4.2 changed how taxonomy information is stored in the database, which directly impacts this plugin’s include/exclude term functionality.
This plugin was formerly known as the <code>Tag List Widget</code>. It was completely rewritten for version 1.0.

Taxonomy List Widget

Creates a list (bulleted, number, or custom) of non-hierarchical taxonomies as an alternative to the term (tag) cloud. Formerly known as Tag List Widg …

Anime Dropdown Widget vs Taxonomy List Widget