A few nice WordPress plugins I’ve been using recently:

Better WP Security – A very popular and powerful plugin that takes a range of steps to harden your WordPress installation.

Mail on Update – Emails you to let you know of available plugin updates.

Polylang – Simple and easy to use, it allows you to create a multilingual site (no in-built translation workflows – if you need that try WPML).

Approval Workflow – An easy way to add an Administrator-approval process to your publications.

Blackbox Debug Bar – For plugin developers. It gives useful feedback on SQL queries, page load times, errors, and values of superglobals.