Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
GitKraken - The intuitive, fast, and beautiful cross-platform Git client.
Instagantt - Instagantt is a powerful and intuitive Gantt chart tool to enable teams to plan, manage and visualize their projects easily. Manage your schedules, tasks, timelines, and workload like a Pro. Try it for free.
SourceTree - Mac and Windows client for Mercurial and Git.
Manifold - Manifold GIS is a combination of mapping, CAD, DBMS and image processing.
GitHub Desktop - GitHub Desktop is a seamless way to contribute to projects on GitHub and GitHub Enterprise.