Hello Mr. Right ML is teacher of FL, she has big crush and practically stalks him, though she is super cute lovely and overall very good positive drama and great chemistry
Go Go Squid! kind of stalks ML, at list in the beginning (though for me FL was annoying character and couldn't understand how/why would ML fall for her)
Hyena she also stalks him but then there is much interesting plot turn and taboo subject (modern kdramas don't have such plots), also she is nice lovely girl
couldn't say stalkers but very long time one sided love and run after ML Itaewon Class and Nine: Nine Times Time Travel both really good dramas, both great FLs hilarious, full of life (and crazy badass in Itaewon). Also girl showing love first and running after guy is in Girls' Generation 1979 which is also really good drama (I'm talking about second couple, think they had better romance/chemistry, but FL (though 2 girls are mains here) maybe stalks on her crush more). Btw in these 3 romances FLs are quite younger then ML.
after all I don't think there is other FL like "It's Okay" but one similary crazy and unforgetable is in Mr. Queen