Legend of Lu Zhen is a really great cdrama and although it's main focus ISN'T revenge, it does occur and characters get what's coming to them.
As far as lakorns/ thai dramas are concerned I would recommend:
Game Rak Game Rai- I really liked this one because the couple was so sweet at first, which made the revenge that much juicier
Jam Loey Rak- actually my first lakorn, and the one that got me hooked
Kularb Rai Narm- this one, the revenge wasn't between the couple, and not only does that set it apart but also includes a good life lesson as well.
Hope this helped :)