Nice,

But I've checked nearly everything thing out. Online kanban boards, Trello, Asana, Org-Mode you name it...

Its extremely hard to beat the flexibility of a diary and pencil/pen. You can doodle, scratch, draw, record, take notes, maintain time, review history, write a lesson, work out problems... The list is endless... You can do all this in a easy extremely distraction less tool. And to be frank maintaining a diary gives me a great deal of discipline in fighting procrastination. Diaries also are great progress indicators.

Most successful people I know maintain diaries. Diaries and Pens are here to stay.