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.
Kissflow - Kissflow is a workflow tool & business process workflow management software to automate your workflow process. Rated #1 cloud workflow software in Google Apps Marketplace.
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
Nintex - Cloud-based digital workflow management automation platform
Slack - A messaging app for teams who see through the Earth!
ProcessMaker - ProcessMaker is an easy to use BPM and workflow software solution. It is used to design, automate, and deploy business processes of any kind.