Haldaug

This plugin creates a widget that displays excerpts from Wikipedia on the tag pages (the template tag.php). The user can specify multiple languages for the plugin to query using the Wikipeida API. The language that has an article that matches the tag has its article displayed.
<h3>Credits</h3>
This widget is based on the WordPress-Wikipedia-Widget by patlockley: <a href="https://github.com/patlockley/WordPress-Wikipedia-Widget" rel="nofollow ugc">WordPress-Wikipedia-Widget</a>

Wikipedia for tag pages

A widget that displays excerpts from Wikipedia articles relevant to the tag on tag-pages. Support for multiple languages.

samwilson

The Embed Wikimedia plugin adds support for embedding photos from Wikimedia projects such as Wikipedia, Wikimedia Commons, and Wikidata.
It requires no configuration, and to use you just add a URL of any of the above sites on its own line in a WordPress post or page.
Development is on Github at <a href="https://github.com/samwilson/embed-wikimedia" rel="nofollow ugc">samwilson/embed-wikimedia</a>; 
please report all issues there.

Embed Wikimedia

The Embed Wikimedia plugin adds support for embedding photos from Wikimedia projects such as Wikipedia.

Wikipedia for tag pages vs Embed Wikimedia