The set of books the first Musar [Ethics] Movement was based on was three, חובות לבבות Obligations of the Heart, מסילת ישרים ואורחות צדיקים. [I do not know the common English translation. I think perhaps Paths of the Righteous, The Path of the Just.] This basic canon was added onto and so the actual books that people were concentrating on were about 30 and even more if you count the Maharal from Prague. In any case the literature was a lot.
But to launch another Musar movement with the purpose in mind as Reb Israel Salanter, I think would have to include the אור ישראל by one of the major disciples of Reb Israel Salanter, Isaac Blasser. And the מדרגת האדם by Joseph Josel Horowitz a later disciple of Israel Salanter after the original three.
Plus it would have to include Jewish philosophy which I think has been ignored at terrible consequence. That would be the אמונות ודעות by Saadia Gaon, the Guide of the Rambam, Ibn Gavirol, Crescas, Joseph Albo, Abravenal.
There are still details to work out. The First Musar Movement somehow got absorbed in yeshivas and is almost zero in effect today. It gets at best lip service, and some "mashgiach" [the person that in theory in charge of the spiritual welfare of the students] talks once a week. Yet it is well known that mashgiachs are just the people too stupid to be rosh yeshivas. They don't even know much about what is going on in Musar itself, much less Gemara. A mashgiach is a person talking about virtue who know nothing about it. How could it not be damaging? Why not get a football couch that knows nothing about football?
So it is hard to see where this might go. Still it is important, and without which nothing else can begin of much worth.
[Plus outdoor skills and physical fitness. Outdoor skills is for character development, plus survival skills.] Outdoor skills and physical fitness have to be a part and parcel of any Ethical movement. Ethics does not exist in a vacuum.
[Outside of all the above I wanted to say that things in Ethics you need to work on, it is a good idea to memorize them and say the paragraph right when you wake up in the morning. Like if you need to work on some trait,you find some statement in a Musar book that deals with that trait and say it over right when you wake up.]