Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Sketch - Professional digital design for Mac.
7todos - A task board for indie hackers
Affinity Designer - Professional creative software, exclusively for Mac.
TaskPaper - Plain text to-do lists for Mac