WS Custom Scrollbar plugin will enable change scrollbar styles where you can change scrollbar color, border radius, scroll speed, width.

Get rid of boring scrollbar and make your own Custom Scrollbar for your website.

TCBD Custom Scrollbar - WordPress is a jQuery custom scrollbar for your wordpress website. This plugin will enable awesome custom scrollbar. You can change scrollbar color, border radius, scroll speed, width, hide delay & other settings.

Adds a custom scrollbar to specified HTML elements.

Wp Custom scrollbar is nicescroll wordpress plugin.