Articles Field is a Joomla! custom field plugin that greatly extends the capabilities of custom fields.

With the native Joomla! lists fields, the values are only treated as plain text and cannot be linked to any other content.

The Regular Labs “Articles Field” (articles) is a Joomla custom field that gives you the ability to choose from a list of articles (based on the selected filters), allowing you to directly connect articles to each other.
The result displayed on the frontend article is a list of titles of the selected articles, that can be hyperlinked to the respective articles, and even displayed along with the value of another custom field.

You can determine which articles show up in the custom field select list by optionally filtering it by categories.

How to use it: https://www.regularlabs.com/articlesfield