Love O2O recommended and the new one is Old Boy 2018

I'm watching To Love, To Heal now.. and Jiang Chao's character is in so deep... He definitely falls for Li Xirui's character way before she falls for him

China:

  • Only Side by Side With You - It's a modern drama about drones, but the male lead falls for her when they first meet. 
  • Love Me If You Dare - Immature genius falls for a normal girl and uses her love of adventure to convince her to become his assistant.

Taiwan:

  • Office Girls - It takes a few episodes, but he falls hard. I love this one because he looks at her so lovingly that it's just plain adorable.
  • The Perfect Match - Also takes a few episodes for him to realize why he likes having her around so much.

General and I and maybe Legend of Fu Yao ♥

The story of Ming Lan, one of my favorites ...

I think there is more that I watched about the boy liking the girl first, but I don't remember.

- Lucky's First Love

- Fall in Love

- Love is Deep

- The Legends

Drawing, Spring (The ML was in love with her since they were young)

Just an encore

Miss Hammurabi

My ID is Gangnam beauty (The ML is completely in love with the FL)

Pinocchio

Romantic Doctor kim 2 (Though the romance is not soo evident in the drama, the ML did fall in love first)

Weightlifting Fairy Kim Bok Joo

Since you said you don't mind a good modern Drama, I'm going to suggest you check out Lay Your Head On My Shoulder - he falls first and HARD, while she remains oblivious for a long time.

Ashes of Love ( a must watch list )

The Legend ( both main leads chemistry awesome )

Arsenal Military Academy ( funny & romantics )

The Kiling of 3000 crows aka Love of a Thousand Years ( Male Lead the immortal falling in love with the Female Lead for 1000 years aka her 10 life times reinqarnations )

I haven't seen the dramas you mentioned, but according to the descriptions, i can suggest a c-drama 

Find Yourself 
The guy falls first and sticks to it, as he was much younger than her she hesitates but eventually they get together. They start dating but the major plot revolves around how their age gap affects her as she was torn between a young immature man whom she loves and a mature man that she's been friends with and whom her family loves. She breaks up with ML(eventually they end up together)But whole this time the guy sticks to his feelings, although he wasn't so over-the-top. But i liked their chemistry and his attempts to show her that he's mature and a grown-up man. lol

Historicals

  • The Romance of Tiger and Rose
  • The Legends
  • The Legend of Fu Yao
  • Empress Ki
  • Tale of Nokdu
  • Tamra the Island

Modern

  • Wait My Youth
  • Put Your Head on My Shoulder
  • Falling For Innocence
  • New Tales of Gisaeng
  • Mask

The Romance of Hua Rong (pirate king falls in love with general's daughter and marries her after things accidentally happen but she runs away from him)

 zoeraindasher:

The Romance of Hua Rong (pirate king falls in love with general's daughter and marries her after things accidentally happen but she runs away from him)

yeah, i loved that drama!! one of my favorites honestly, it had  the plots and characters i like

Yeah me too.. I loved it so much.. Been playing the OST over and over again. Can't wait for Season 2 of Hua Rong