Owadud

External Link Icon for Gutenberg adds a new Gutenberg block called Link with Icon.
Each block contains its own link URL, link text, icon choice, and display options — all configured in one place. There are no global settings that affect your whole site.
How to use:
<ol>
<li>In the block editor, click the + button to add a block</li>
<li>Search for “Link with Icon”</li>
<li>Insert the block</li>
<li>Enter your URL in the on-canvas URL field and click Add Link</li>
<li>Open the block sidebar (right panel) to:
<ul>
<li>Set link text</li>
<li>Toggle new tab / nofollow</li>
<li>Pick an icon from the Dashicons or SVG Icons tab</li>
<li>Set icon position (before or after text)</li>
</ul>
</li>
<li>The live preview updates as you make changes</li>
</ol>
Icon sets:
<ul>
<li>Dashicons — WordPress built-in icon font (32 icons, no extra network request)</li>
<li>SVG Icons — 32 bundled stroke-based SVG icons, rendered inline (no CDN, no webfont)</li>
</ul>
Principles:
<ul>
<li>No global icon settings — each block is fully independent</li>
<li>Image links are not affected (this is a dedicated block, not a link filter)</li>
<li>Server-side PHP rendering — compatible with all caching plugins</li>
<li>No jQuery required</li>
</ul>

External Link Icon for Gutenberg

A Gutenberg block for creating a link with a Dashicon or Font Awesome icon. Per-block, not global.

Kishores

Post Featured Icon: It allows to add font icons to post title, and there is option so that we can 
replace post thumbnail with font icon.
It supports:
<ul>
<li>dashicons</li>
<li>genericons</li>
<li>font-awesome</li>
</ul>
Please check here: <a href="http://opentuteplus.com/post-featured-font-icon/" rel="nofollow ugc">Demo 1</a> and <a href="http://blog.kishorechandra.co.in/project-fork-in-open-source/" rel="nofollow ugc">Demo 2</a>
It supports post,page.But we can add to custom post types to. It provides hooks i.e icon_post_type .
<blockquote>
Priority Support
If you are looking for more features, paid support or Custom WordPress Work, then you can hire me too. My email id : babunsahoo@gmail.com .
</blockquote>
<pre><code>// Our filter callback function
function icon_post_type_callback( $types ) {
 $types = array('post', 'page', 'product');
 return $types;
}
add_filter( 'icon_post_type', 'icon_post_type_callback', 10, 1 );
</code></pre>

Post Featured Font Icon

it supports dashicons, genericons, font-awesome.

External Link Icon for Gutenberg vs Post Featured Font Icon