Plugin Usage Report for the Network
Adds Network Admin > Plugins > Usage, a table of every installed plugin with how many sites activate it and which ones, so you can safely remove unused plugins.
Snippet Library
Multisite snippets for WordPress
Snippets for WordPress Multisite networks: network-wide settings, new site defaults, super admin tools and cross-site tweaks. For network administrators who manage many sites from one install.
Theme Usage Report for the Network
Adds Network Admin > Themes > Usage, listing every installed theme with the sites that use it (directly or as a parent theme), so unused themes are easy to spot.