#1 - July 28, 2016, 12:43 a.m.
http://d3resource.com/journey/
Super simple concept - just as you doing the Season Journey click on a task to keep an overview of what you have done and what still needs to be done. The status is saved in a cookie. Pay attention to the in-game popups because you can complete many season journey objectives that aren't even visible yet, so this website might help you to keep an overview.
UPDATE 1/1/2017:
Now updated for S9.
