BM Custom Login – Binary Moon’s Custom login is a simple way to customise the login screen on your wordpress install. The plugin also includes a psd template for creating your own login screens so it couldn’t be easier.
AJAX Login – Wordpress plugin to use AJAX powered login page. AJAX Login means that the login process is executed without reloading the entire page.
Login LockDown – Login LockDown records the IP address and timestamp of every failed WordPress login attempt. If more than a certain number of attempts are detected within a short period of time from the same IP range, then the login function is disabled for all requests from that range. This helps to prevent brute force password discovery.
WP Email Login – Lets you use your email address to log into your WordPress account instead of a username. Since email addresses are required to be unique within WordPress anyway, they also make good identifiers for logging in.
Force User Login – This is a very small plugin that forces users to login before viewing any content. This is done by checking if the user is logged in, and if not, redirecting them to the login page. Users attempting to view blog content via RSS are also authenticated via HTTP Auth.
WP-OpenID – This plugin allows users to login to their local WordPress account using an OpenID, as well as enabling commenters to leave authenticated comments with OpenID. The plugin also includes an OpenID provider, enabling users to login to OpenID-enabled sites using their own personal WordPress account.
Members Only – Members Only is a WordPress plugin that allows you to make your blog only viewable to visitors that are logged in. If a visitor is not logged in, they will be redirected either to the WordPress login page or a page of your choice.
MiniMeta Widget – Wordpress plugin to add logon boxes to the meta links information.
Restrict Login By IP – This plugin lets you specify IP addresses or hosts that users are allowed to login from. You can either use full IPs (e.g. “12.34.56.7″) or partial IPs (e.g. “12.34″), which lets you specify a range of addresses.
WordPress Noindex Login Plugin – If your WordPress blog has a public login page, you probably don’t want it to be indexed by search engines. So this plugin adds the noindex meta tag to your WordPress Login page.
Please note that I am no way endorsing any of these Wordpress plugins. Personally I have used Login Lockdown which is a nice plugin.
Image Credits: Css-Tricks