Pamtree's To-Do list allows you to have all of your tasks in one place - and even set reminder notifications and assign tasks to team members.
You can optionally mark any Task with Tags, Customers and/or Products, in which case your action will be cross-referenced to those features allowing you to search or filter to see actions pending for particular processes, customers or products.
Once you have completed your Tasks, they go into your "Completed Tasks", so that you have a full history to refer to at any time.
This video shows you how to manage your To-Do List.