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.
Hive - Seamless project management and collaboration for your team.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Sup! Standup Bot - The complete stand-up and follow-up bot
Sendtask - Sendtask is the easiest way to organize your work and collaborate online. Simple to use but powerful enough to run your business on it.
Asana - Asana project management is an effort to re-imagine how we work together, through modern productivity software. Fast and versatile, Asana helps individuals and groups get more done.