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.

derickschaefer

Link Vault is a link management plugin to help bloggers write posts more efficiently. A typical blogger will open a series of browser tabs and flip back and forth between them as they create hyper links in their blog posts. If you use affiliate marketing links in your post, you will also find your self looking for those links at the last minute. This takes time and creates “blogger fatigue”.
Link Vault allows a blogger to do two things. The first is to create a list of persistent links that are available to you at all times in your blog post editor (Add New Post or Add New Page). This is the perfect place to store affiliate links or links you reference often. The second is that Link Vault allows you to collect the links you want to use for a give post ahead of time and simply drag and drop them when you are ready.
In a future release we will create a javascript based browser bookmark that will allow you to simply click the bookmark while browsing to store the URL of the page you are reading in your browser.
Link Vault Features:
<ul>
<li>Persistent link storage for affiliate links and other commonly referenced content.</li>
<li>Post level link collection to simplify the writing process.</li>
</ul>
<h3>Our Commitment</h3>
Let us know what bugs you uncover and what functionality you think would make this a better plugin.

Link Vault

Link Vault is a WordPress plugin that adds a widget to your post editor allowing you to easily drag and drop commonly used hyperlinks.

Link Manager vs Link Vault