Andrew Nacin

In WordPress 3.5, the Link Manager (which some use to build blogrolls) will 
be disabled by default. If you have links when you update, it’ll still be there. 
But you can use this plugin to ensure it will always be there, even if you 
update to a later version of WordPress or remove all of your current links.

Link Manager

Works on WP 6.1

Enables the Link Manager that existed in WordPress until version 3.5.

ravimareedu

With this plugin you can efficiently create your website/blog inner links/content links. A specific words can be linked to any specific link through out the site/blog. The beautiful part is, you can restrict the internal linking within a taxonomy/category, So that it will avoid linking unrelevant worrds. 
<a href="http://xmlswf.com" rel="nofollow ugc">Power Links</a> allows you to manage site internal links for blogs. 
Let me provide you an example. 
If you want to link to “orange” in the category of “Fruits” it will not link to the “orange” in the category of “Colors”. I hope this is what I did not found on many inter linking plugins and we built one with covering these problems. 
See it in actoin at : https://beautyhealthtips.in

Power Links – Internal Link Manager

Power Links plugin Manages your WordPress blog internal content links effectively and improves your SEO performance with proper link juice.

Link Manager vs Power Links – Internal Link Manager