On the network:
- Better WordPress Minify
- BP Auto Activate Autologin Redirect To Profile On Signup
- BuddyPress
- BuddyPress Multilingual
- BuddyPress Sitewide Activity Widget
- MultilingualPress
- Optimize Database after Deleting Revisions
- W3 Total Cache
- WordPress MU Domain Mapping
- Yoast SEO
Different plugins on each single site.