ThomasHambach

Inspired by the script written by Blair Vanderhoof, this plugin allows you to input gist files directly into your WordPress posts using a jQuery callback.
Currently supports: * Showing a whole gist. * Showing single file in a gist. * Showing certain lines of a single file in a gist.

Gist Embed

This plugin allows you to input gist files directly into your Wordpress posts with a click of a button.

Andy Fragen

Colin Stewart

Use an Embed block and enter the URL for the Gist or the URL for a specific file within the Gist. If using the Classic Editor, place the URL on a line by itself. Not as a link.
Support for <code>wp_oembed_get()</code>.
No shortcodes.

Gist Embed vs oEmbed Gists and Files