The number of web apps nowadays dramatically increased, thanks to some very talented people who wanted to make our lives easier. But to build a successful app requires more than a very smart idea. A clean and elegant User Interface Kit has to beautify the app, in order to create a nice user experience. Therefore, I gathered 60 free, clean and trends-following UI Kits, ready to be downloaded and used in your projects!

Black UI Elements

Grayness UI Kitt

UI for Japan

Green Contact Form

Clean and Sexy Form Elements

Blue and White GUI Kit

Signup Modal Box

Bloom UI Kit

Progress and loading bars

Toggle Switch Variations

Apple Styled UI Elements

Gray & White Form Elements

Orange Interactive Elements

Silver and Gray User Interface Elements

Dark UI Elements

Contact Form with Tabs

Form Elements

Progress Bar

Gray Elements

UI Kit

Dark Menu Items

CSS3 Buttons

Newsletter Sign Up Form Interface

Interface Elements for Forms

Contact Form Interface with Selected States

Solid UI Kit

Simple UI Elements

Horizontal Drop-Down Menu

Big Block UI

Blue Modern Web UI

Sleek Calendar

Login Signup Form Element

Blue UI Kit PSD

Gray UI Icon Set

Black UI Icon Set

Navigation Bar

Design Elements

Small GUI Pack

Web Elements

Elements for Visual Style

Iphone UI Kit Remake

Search Box

Snow UI Kit

Designer CSS UI Kit

Dark Web Design Elements

Modern Web UI Kit

UI Webkit

Web UI Treasure Chest

Controls

Another Controls

Call to Action Buttons

Simple Form Elements

Spring GUI

iTunes X Elements

Small UI Set

Bright Buttons

Social Buttons v2.0

Blue Tags

Business UI

Neat UI

Related posts:

1. 40 Free Web and Mobile UI, Wireframe Kits and Resources
2. 50 Useful and High Quality Free PSD Files
3. 50 High-Quality Free PSD Website Layouts