Vast HTML

This is a full featured plugin to help you edit your login just the way you want it. Lets you use or block the original wordpress 
css (the first plugin to do this). Comes with one pre made style you can use or deactivate. 
Very easy to create your own style using the style tags givin in the plugin. 
Please visit http://vasthtml.com/js/login-xchange-plugin/ for usage instructions.

Login XChange

This plugin will let you change the css of your login and register pages.

Johan van der Wijk

Customize Admin is a powerful WordPress plugin that puts you in control of your website’s login page and dashboard layout. With its intuitive features, you can effortlessly tailor the look and feel of your WordPress login page and dashboard, creating a seamless and branded experience for your users.
Key Features:
Personalized Login Screen: Easily upload your custom image or logo to the login screen and define the link associated with the logo. Take your brand identity to the forefront and leave a lasting impression on your visitors from the very first interaction.
Streamlined HTML: Trim down and fine-tune your website’s HTML source code by selectively removing meta tags from the head section. Enjoy better control over your site’s code and optimize it for improved performance and SEO.
Dashboard Widget Management: Take charge of your dashboard widgets! Customize Admin enables you to disable selected widgets, allowing you to declutter and streamline your WordPress dashboard effortlessly.
Want to see the magic of Customize Admin in action? Check out the <a href="http://www.vanderwijk.com/wordpress/wordpress-customize-admin-plugin/" rel="nofollow ugc">plugin homepage</a> for more information and an enlightening screencast video that showcases the plugin’s capabilities.

Customize Admin

With this plugin you can use customize the appearance of the WordPress login page, dashboard and head section tags.

Login XChange vs Customize Admin