I think this information IS useful for end users for the reason that some developers may bail out of supporting an aged plugin and won't leave any way to contact them. I posted this to WordPress.org several hours ago but thought I might get a quicker answer here:

I started using this now unavailable plugin over 3 years ago:
https://wordpress.org/support/topic/plugin-wp-render-blogroll-links-custom-order .

It created Term ID numbers which it used to maintain Categories of Links.
With it , I also used these two additional plugins:
https://wordpress.org/support/view/plugin-reviews/link-manager
https://wordpress.org/plugins/hierarchical-link-categories/

After uninstalling ALL 3 of the above plugins from my main site, I ran this search plugin I learned about on WP Tavern: https://github.com/jjeaton/wp-find-shared-terms . It informs me that I have mixtures of the following:

Term Taxonomy ID=126, Term ID=20, Name=All, Taxonomy=Link Categories, Number of Posts=0

Term Taxonomy ID=20, Term ID=20, Name=All, Taxonomy=Categories, Number of Posts=0

I believer that the Hierarchical Link Categories create the “All” name back some time ago, and I can’t seem to get rid of it. Also, I believe that somewhere in my Database is a list of ID Numbers created by the WP Render Blogroll Links plugin which is now deleted. How do I find any possibly hidden list of Category Term ID numbers in my Database so I can delete them all individually (am I correct that this might be the reason I still have an “All” name?

(Additional Information: I have created NO Posts on my main site…I use it for a display of only Pages and Links.)