UI kits can save you time and money while drastically improving the look and feel of your design. Not only will you be able to differentiate yourself from the default Bootstrap styling, you can change the overall styling of your theme much more efficiently. So here are some awesome HTML CSS UI kits are based off Bootstrap and definitely worth checking out for your upcoming projects.

PixelKit

Free UI Kits built on Bootstrap for any developer that wants to build a cool looking and functional website.

Bootstrap 3 Vector UI Kit

All basic UI elements from this kit are already sliced, styled, HTML-encoded and ready to use. Please refer Bootstrap UI Framework for documentation. UI Kit contains Adobe Illustrator, PDF and Sketch files.

Flat UI

Plan Flat Bootstrap Skin

Plan is a skin for Bootstrap, which means that can be used with any site built with the Bootstrap framework. With easy installation and customization thanks to the LESS files included and the custom themes colors ready to use.
This skin is based on a flat desing and also extends the styles directly applied to Bootstrap files. There’s no overwritten rules or bloating CSS, making a lightweight skin as Boostrap is itself.

Dropper

Antagon

Antagon is a massive expansion set for Bootstrap with 30 jQuery plugins and many new built-in features. While there are huge changes and additions, this doesn’t mean the package can’t be clean and fast. You decide which features to include and how to work with the theme

Silverwhite

Elemento

Elemento brings all the potential of Bootstrap, with a fresh and clear new look, plus a ton of new features and plugins pre configured.

Morning

Bootflat

BOOTFLAT is an open source Flat UI KIT based on Bootstrap 3.1.1 CSS framework.

Get Shit Done Kit

Get Shit Done Kit is a free beautiful resource built for Bootstrap. We have redesigned all its components to make it look flat, minimalist and easy to use. The Get Shit Done Kit fully supports Bootstrap 3.