Suspend User Accounts
Adds a "Suspend this account" checkbox to the user edit screen that logs the person out everywhere and blocks them from logging in until it is unticked.
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.