Rainglow Color Themes - 320+ color themes for a variety of editors and software.
Invision - Prototyping and collaboration for design teams
Slack Themes - Make your Slack pretty with custom themes
Mockuuups Studio - Fast and easy way to create product mockups on macOS, Windows and Linux.
eM Client - eM Client is a fully-featured email client for Windows and macOS with a clean and easy-to-use interface. eM Client also offers features for calendars, tasks, contacts, notes, and chat.
Craftwork - A collection of User Interface resources made by Craftwork