Any dramas where the male lead has love at first sight for the female lead then tries to chase after her? Love at first sight when they were children doesn't count, they're full on strangers when they first meet in present time.
A Business Proposal - The ML is interested (but not fully aware of how interested he is) from their first encounter. It takes him a little while to figure it out and start chasing her.
Where Stars Land - Tbh I don't remember the exact details, but iirc I think this one fits.
The ML and FL are strangers that have a "one night stand" but the ML is smitten and chases the FL / pursues a relationship with her:
Love at first sight when they were children doesn't count, they're full on strangers when they first meet in present time.
These don't really fit, but I'm mentioning them just in case:
The Princess Wei Young - Technically the ML and FL encounter each other very briefly on two occasions (the first time the FL is dressed as a man, and the second time the ML saves the FL from a burning building) before the ML falls for the FL, but it's pretty close to "at first sight". The FL also falls for the ML, but pushes him away after becoming aware of his identity and the ML chases her.
Crash Landing on You - The ML felt something for the FL (despite being with his arranged-marriage-fiancee at the time) when he first encountered her in the past. He helps her briefly, but does not try to do anything else. They were both adults at the time. The ML was at university in Switzerland to study music. The ML and FL do not recognize each other when they meet again in the present.
Kimi Wa Petto - The ML fell for the FL at first sight when he first met her in the past. He was pretty young and the FL was a university student at the time. The FL doesn't recognize the ML when they meet again in the present, and he doesn't try to chase her, but he does eagerly accept the opportunity to be close to her.