Everything N1, free. Reference material and review; no course at this level.
Not sure where N1 sits, or what to do first? The road map puts every step in order, with how long each one takes.
There is no written N1 course. Lessons mean Japanese prose and dialogue, which needs a fluent reader we do not have — so rather than generate something plausible and wrong, we have left it undone and said so. Everything above is real and works today.