Taskbook - Like Trello but for the Terminal
Send to Things - Add tasks to Things from your Android device
Todorant - Tricks yourself into craving completing tasks
NOW UI kit by InVision - A beautiful cross-platform UI kit (PSD & Sketch)
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Elements for Sketch - High-quality UI Kits in Sketch, for free