The only one was In King2heart as far as I can remember  I prefer max 20 episodes less is fine too

Coffee prince? I'm not sure if it was a mom or granny in-law, but as far as I remember she was quite nice.
Fated to love you - granny in-law, but since the main guy didn't have a mother, she was a mother figure.
Full House - there is a korean version, but I liked the thai one so much better
Marriage, Not Dating - okay, I wasn't sure whether to recommend this or not, because the mom was kind of a bitch at first, but as the drama goes by you see why she is like that, she changes a bit and you understand, that she is really likeable.

Operation Proposal - Though this drama annoyed me a bit, I really liked the male lead's relationship with the female lead's parents.
Marriage, Not Dating - I second this one, I really liked the mother, she was much more real than those other rich mothers from other dramas. It wasn't that she exactly hated the female lead, it was that she rightfully didn't believe her son.
The King of Dramas - the mother plays a rather small role (that I remember and wasn't rich on her own), but she was very nice to the female lead