Daniel Westermann-Clark

By default, WordPress network usernames cannot contain anything but lowercase letters and numbers. This plugin adds network options to let you include hyphens, underscores, or uppercase letters, if desired.
Furthermore, this plugin gives you the option to allow email addresses as usernames, or to allow all-numeric usernames (e.g. “1234”).
Finally, this plugin lets you override the minimum length for usernames (which defaults to four characters).
To follow updates to this plugin, visit:
https://danieltwc.com/
For help with this version, visit:
https://danieltwc.com/2011/network-username-restrictions-override-1-0/

Network Username Restrictions Override

Does what it says!

Override restrictions on WordPress network usernames.

shazdeh

A simple plugin to eliminate the need to “Network Activate” whenever a new theme is added to the network. This is a tiny time-saver for developers and theme testers who deal with lots of new themes regularly.

WPMU Allow All Themes

Automatically enable all themes available on your network to all websites in the network.

Network Username Restrictions Override vs WPMU Allow All Themes