Maxaud

(NOTE: Before saying this plugin is broken, please understand what this plugin does. It’s meant for WordPress installs that have multiple NETWORKS.)
Adds the ability to have different themes available to different NETWORKS in a multisite atmoshpere.
WordPress allows for multiple “networks”, these are not to be confused with sites. A network holds blogs underneath of it.
This plugin will allow you to separate themes into different directories so they’re only accessable and viewable to the networks you choose.
The plugin will attempt to create a directory in the /wp-content/ directory named /ms-themes/. If it fails to create it, then you will need to make one.
In the /ms-themes/ directory you will create a folder for each network that you want to allow only certain themes to.
Example: 
If you have a theme named “Snarfer Theme”, and you want to only allow it to be viewable/available to the network (and all sites on that network) with the site_id of 7, you would place the snarfer theme directory in /wp-content/ms-themes/7/
Future releases:
<ul>
<li>Network option to turn off auto creation on/off network directories, index.php files.</li>
<li>Network option to display network ID in the footer of sites so network admins can easily tell what network a site is under.</li>
</ul>

Multisite Themes

Adds the ability to have different themes available to different NETWORKS in a multisite atmoshpere.

Adadaa

This plugin creates four (4) seperate RSS 2.0 feeds from posts, comments, pages, and one combined [posts & pages] across all blogs on your site.
Works both on WPMS upto 4.9.20
This will skip the first comment and page of a blog; also will not include private, spam, mature and deleted blogs.
Both Subdirectory and VHOST installations are now supported. Thanks to DaryL.
Features:
<ul>
<li>Generates sitewide combined [posts & pages] feed</li>
<li>Generates sitewide posts feed</li>
<li>Generates sitewide comments feed</li>
<li>Generates sitewide pages feed</li>
<li>Client-side caching via ETag headers</li>
<li>Admin screen to configure options</li>
<li>Compliance with xhtml and xml standards & many more</li>
</ul>
For more explanation and to leave any suggestions to improve or bugs, please visit on my blog : <a href="http://1uthavi.adadaa.com/ada-wpmu-sitewide-feed-plugin/" rel="nofollow ugc">Ada WPMS Sitewide Feed</a>
<h3>Usage</h3>
Compatible with WP Multi-Network plugin . You can have different blog ID than 1 to trigger the full feed.
<h3>To Do</h3>
<ul>
<li>Comply fully for language translation</li>
<li>Exclude blogs by ID</li>
<li>Enable/disable individual sitewide feeds</li>
<li>Option to include the blog title in the post title shown in the feed</li>
<li>Consider changing the function ada_get_avatar_url() to use the core hook get_avatar(). So it can work with WPMUDEV’s Avatars for Multisite.</li>
<li>Option to exclude by post types</li>
</ul>

Ada WPMS Sitewide Feed

Creates four rss 2.0 feeds showing recent posts, comments, pages, and one combined [posts and pages] from all blogs.  Works both on WPMS, and WPMU

Multisite Themes vs Ada WPMS Sitewide Feed