Softagram - Automated visual reviews for GitHub pull requests
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.
Mergify - Stop merging your pull requests manually
Lanes - Superpower your productivity.
PR Patrol - Monitor code that matters to you
Asana Timeline - Visualize your project plan so you can hit your deadlines.