From: https://community.kde.org/Get_Involved

Visual and Human Interface Design

Whether you are an artist, a designer, or just someone with an interest in how people interact with software, the KDE community needs you! The VDG help make KDE software both beautiful and usable by helping teams design their user interfaces. This includes creating icons and themes, as well as thinking and researching how to help users do what they are trying to do, instead of getting in the way. By joining this team, you can help make software that makes users happy, and those around them jealous. Find out more about joining the VDG.

Link at the end: https://community.kde.org/Get_Involved/design