I’ve watched every HYD variations possible, including “Moon River” and the 2018 one. I’ve also loved : “Cinderella and 4 knights”, “The Heirs” “Shining Inheritance” and “You’re beautiful”. Basically, I want a few rich male leads falling for the FL after being “re-educated” by her. Course, FL has to be poor, ordinary-looking but optimistic and brave! Are there anymore HND spin-offs? Pretty please with a cherry on top?

there is the opposite with the movie "I am underage but not a child" (rich girl gets educated by poor male)

By the way I love that someone else has seen them all --so sorry if you watched "lets go watch a meteor shower."

Try "Rich man/Poor woman"  it's similar 

 (your completed list only has 20 titles so I am not sure what you have seen.)

Maybe:

  • Flower Boy Ramyun Shop
  • What's Wrong with Secretary Kim
  • Romantic Princess

Try: 

Goong

Full House 

Secret Garden 

Scarlet Heart Ryeo- it's like Boys over Flowers in historical setting but more dramatic 

1 Percent of Anything 

High End crush, I'm not a robot, w, coffee prince, playful kiss, love rain (a bit boring first 4 episodes which is set in the 70's, gets better with the kids story,)

I third My ID is Gangnam Beauty!

Chinese series that I loved, rewatched, and found similar to your preferred shows...

Time Teaches Me To Love  Rich arrogant ML, poor ordinary FL, height difference (BOF-like)

The Brightest Star in the Sky Rich arrogant, grumpy ML/pop star, poor friendly FL/assistant (You're Beautiful-like)

Unique Lady Arrogant ML/prince/bully, poor sassy FL who's courted by much nicer rich friend of the ML (BOF as time travel show)