Josh Betz

A simple plugin that allows blog owners on a multisite network to use a custom favicon by uploading it to the root of their theme directory. Ideal for people who host clients on their own multisite install or want to run multiple domains off of one install.

Network Favicons

Allows blog owners to use a custom favicon just by uploading it to the root of their theme directory.

jediconcepts

A WordPress plugin that adds unique favicon support for each domain mapping in the <a href="https://wordpress.org/plugins/multiple-domain-mapping-on-single-site/" rel="ugc">Multiple Domain Mapping on single site</a> plugin.
Plugin Repository: [https://github.com/jediconcepts/multi-domain-favicon-manager] 
Support: dev@jediconcepts.com
<h4>Features</h4>
<ul>
<li>Unique favicons per mapped domain – Set different favicons for each of your mapped domains</li>
<li>Media library integration – Upload new favicons or browse existing media</li>
<li>Smart domain conversion – Automatically converts URLs between base and mapped domains</li>
<li>Conflict resolution – Removes WordPress default site icons to prevent conflicts</li>
<li>Search functionality – Find favicon files by filename when media browser filters them out</li>
<li>Multiple file format support – Works with .ico, .png, .svg, .jpg, and .gif files</li>
<li>Auto-preview – See favicon previews when entering URLs manually</li>
</ul>
<h4>Requirements</h4>
<ul>
<li>WordPress 5.0 or higher</li>
<li>PHP 7.4 or higher</li>
<li><a href="https://wordpress.org/plugins/multiple-domain-mapping-on-single-site/" rel="ugc">Multiple Domain Mapping on single site</a> plugin (required dependency)</li>
</ul>
<h4>How It Works</h4>
Frontend Behavior 
When a visitor accesses a mapped domain:
<ol>
<li>Plugin detects the current domain mapping</li>
<li>Checks if a custom favicon is configured for that mapping</li>
<li>Outputs the custom favicon HTML tags</li>
<li>Suppresses WordPress default site icon to prevent conflicts</li>
</ol>
Admin Interface 
The plugin adds favicon management fields to each domain mapping:
<ul>
<li>Integrates seamlessly with the existing Multiple Domain Mapping interface</li>
<li>Provides intuitive upload and selection tools</li>
<li>Shows preview of selected favicons</li>
<li>Validates favicon URLs automatically</li>
</ul>
<h4>Button Functions</h4>
<ul>
<li>Upload New (Blue) – Upload fresh favicon files from your computer</li>
<li>Browse Media (Green) – Select from existing files in your media library</li>
<li>Search by Name (Orange) – Find specific files by filename when media browser doesn’t show all files</li>
<li>Convert URL (Purple) – Convert between base domain and mapped domain URLs</li>
</ul>
<h4>File Format Support</h4>
Supported favicon formats:
<ul>
<li>.ico – Traditional favicon format</li>
<li>.png – Modern format, recommended for most uses</li>
<li>.svg – Scalable vector format</li>
<li>.jpg/.jpeg – JPEG images</li>
<li>.gif – GIF images</li>
</ul>
Recommended size: 16×16 or 32×32 pixels

Multi-Domain Favicon Manager

Got to give this 5 stars

Unique favicon support for each domain mapping in Multiple Domain Mapping plugin.

Network Favicons vs Multi-Domain Favicon Manager