ООО «ЭйВиДи-системы»

This plugin allows you to customize the logo on the WordPress login screen. There is zero configuration. You just drop the logo file into your theme WordPress and this plugin takes over.
Note that you should use a transparent background on the PNG custom logo, crop it tightly (no padding pixels) and use a width of exactly and min 312 pixels for best results. Wider images will be downscaled in modern browsers, but it isn’t recommended to rely on that.
This plugin also works in the <code>mu-plugins</code> directory.

SK-Elib

Customize the logo on the WP login screen. Using a custom logo from your WP theme. CSS is automatic!

diablue

Plugin allows admin to upload custom logo for WordPress login page.
After activating the plugin, follow these steps:
<ol>
<li>Go to Settings -> Custom Login Logo</li>
<li>Click “Choose Image”</li>
<li>Select or upload your logo</li>
<li>Click Save Changes</li>
<li>Refresh the login page to see the new logo</li>
</ol>

Diablue Login Customizer

Easily add a custom logo to your WordPress login page using the built-in media uploader. Change WordPress login logo from admin panel.

SK-Elib vs Diablue Login Customizer