I've watched Hospital Playlist, Twinkling Watermelon, and Castaway Diva, and I loved all of them (especially the first two, which are among my favorites, but I really enjoyed the third as well). Could you recommend other dramas that feature music as a big part of the plot and that you think are good?

I'm open to both shorter dramas (web dramas or Korean TV shows) and regular-length dramas like the ones I mentioned.

Shut up: Flower Boy Band

Monstar

Hit the Top/The Best Hit

Rock Rock Rock (Based on a true story)

K-pop - The Ultimate Audition

Trot Lovers

Reply 1997

Heartstrings

You're Beautiful

Dream High  

What's Up ( I started it years ago but watched a little, will definitely start again)

Let Me Be Your Knight (I haven't watch it yet but i will)

Soundtrack (I haven't watch it yet but i will)

The Heavenly Idol (More like fantasy-romance but ML is trying to be idol and we see kpop industry)

Ces't Si Bon (Korean movie / Based on a true story)

Miss Granny (Korean movie)

Swing Kids (Korean movie / I haven't watch it yet but i will)

Go Go 70s (Korean movie / I haven't watch it yet but i will)

Love, Lies (Korean movie / I haven't watch it yet but i will)

The Hymn of the Death  Korean mini drama / Based on a true story /I haven't watch it yet but i will)

Other Popular or classic ones that I didn't watch but probably will like:

Nodame Cantabile (Japan/ adapted from manga / has an anime / has Korean and Chinese adaptations too/ has sequels)

The Liar and His Lover (Japanese movie/ adapted from manga / has Korean drama adaptation too)

Skip Beat (Japan - Korea/ adapted from manga / has an anime ver.)

Nana (Japanese movie / adapted from manga / has an anime ver. / has a sequel)

Beck (Japanese movie / adapted from manga / has an anime ver. )