Order of playing pieces for technical purpose?

[winterwind888]

What I mean is that what are those pieces that really start from the easiest to the hardest one that involves technical purpose.

For instance, pieces that I have known... easiest to the hardest....

- Well tempered clavier
- Bach Sinfonias and Inventions
- Czerny Etudes
- (And some other set of pieces following next to them, yet I do not know)
- Debussy Etudes
- Scriabin Etudes
- Liszt Etudes
- Rachmaninoff Etudes
- Chopin Etudes
- And so on......

Anything you know please??