Seen few, but looking for more dramas.... topic: contract marriage real or fake.... I don't mind underrated dramas. Thanks! 

(seen: Full House, Delightful Girl Chung-Hyung, Goong, Mary Stayed out all Night, Lie to Me) 
Marriage not dating, Mask
@Shelly: Seen Marriage not Dating but did not see Mask... Thanks!
Sweet 18
Marriage, Not Dating
Fated to Love You
Bride of the Century
Prime Minister and I
Creating Destiny

I'll add later if I can think of more! ^^ 
@Oppa-kiss-me ...... have not watched 3 of the listed, so Thank you for the list. 
Golden Bride. It's a long but very good k-drama. The hero and heroine are very supportive and loving towards each other. Also, the in-laws don't hate her so that's also a plus. 
I absolutely 2nd Golden Bride. Those two are so cute & lovable. Definitely worth the watch even though the drama does get a bit draggy in some parts. 
So next on my list is.... Golden Bride :) ... Thanks!