I use Taskwarrior (https://taskwarrior.org/) because it's digital, simple, customizable and open-source. Gives me just enough flexibility without complicating things. It's a shell-based tool which makes it very portable and easy to automate.
The workflow is centered around "tasks", which can be as simple as a description. You can add tags to tasks, filter by tags, set task priorities & due dates and assign tasks to a project. Much more to love, I recommend checking it out if the above description interests you.