A clean no-nonsense UI with a good colour palette. Designer: Matthew Daniels Source: Design Kindle

Sleek UI Elements

This is a great clean UI kit which is available to download from 365psd. Designer: Sebastien Gabriel Source: 365 PSD  

Cloudy UI Kit

This is an excellent free UI for designers which could be used for a range of projects. Designer: Designmodo Source: Designmodo

Pandora Full UI

These UI elements may not have the same shadow and 3D effects we usually see but they look clean and make good use of padding. Designer: David Kim Source:  Dribbble

Clean Reader Elements

This is great example of what a clean dashboard interface should look like. Simple bold icons and great use of colour make this FeedyMail dashboard really stand out. Designer: Tommy Roussel Source: Dribbble

FeedyMail Dashboard

Dann has created an excellent clean dashboard. It would be great to see doctors and nurses using something like this. Designer: Dann Petty Source: Behance  

iMEData medical dashboard

This is a great example of bright clear tooltip which complements Twitter’s design. Designer: Rob Smittenaar Source: Dribbble

Twitter Tooltip

This is a nice example of a clean progress bar. The colours used work really well together and the embossed effect is a good touch. Designer: Vova Devyatkin Source: Dribbble

Clean Progress Bar

This is a very clean example of a toggle switch with nice icons. Designer: Jason Long Source: Dribbble

Clean Toggle Switch

This is a really nice slider design with gradient colour which emphasises the progress. Designer: Ilja Miskov Source: Dribbble

Slider with gradient colour