Require a First and Last Name in Profiles
Stops users from saving their profile (or an administrator from saving a user) without a first and last name.
Snippet Library
Users snippets for WordPress
Snippets for user accounts, roles and profiles: extra profile fields, new columns in the users list, last-login tracking and tighter control of what each role can do. Handy for membership sites, client sites and teams with many authors.
Username Rules for New Registrations
Requires new usernames to be a sensible length, use only letters, numbers, dots, dashes and underscores, and not be just a number.