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.
Process Street - Create beautiful rich process documents in a simple to follow checklist format. Fast, free and incredibly simple to use.
Pipefy - Pipefy is a process management software that empowers anyone to create and automate efficient workflows on their own without code.
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.
ifttt - IFTTT puts the internet to work for you. Create simple connections between the products you use every day.