What classical piano pieces do you practice to improve your technique?

[jeffreestar]

Hello,
I am currently looking to improve my finger technique and flexibility on the keyboard, but I still want to choose pieces with beautiful melodies to practice and enjoy the music.
I have tried:
Some Chopin Études (Op.10 No.3 and Op.25 No.9).
Debussy's "Arabesque No. 1" to practice light hand and legato.
Some short pieces by Schumann in Kinderszenen.
I would like to ask the community:
Apart from the above, what pieces do you usually practice to develop your technique but still be rich in musicality?
Are there any recommendations for books or Études collections suitable for intermediate to advanced players?
Any tips for practicing without straining your hands when playing fast passages?
Looking forward to receiving valuable comments and experiences from everyone. Thanks in advance for sharing!