Recommendations

Both 'Kiss Me' and 'It Started with a Kiss' are versions of the Japanese manga 'Itazura Na Kiss'. 'Kiss Me' is Thai and 'It Started with a Kiss' is Taiwanese.

In both there is a suspicious cast of characters AND a whole lot of dark secrets

It's exactly the same drama but with different characters
-both are older women still single
-both do a one night-stand with the man that they first hate
-both men are dressed as Santa

Both dramas have a dark and gritty element. Both have to do with infidelity on spouses. Both have to do with a man who gives the world to his woman, yet she still wants more. Valid Love deals more with common people, whereas Queen of Ambition deals with common people, one needing to be more.

losing weight and becoming a better person all in the name of finding love and revenging an ex...

Both shows are about battle between life and death, with ghost roaming around. Friendship and betrayal, but also about love and happiness. Both shows have a tragic theme with some comedy. Both dramas are great and If you like tragedy I would recommend both of these dramas.

Plot-wise these two have pretty much nothing in common. If you enjoy the acting of the female lead on the other you will enjoy the acting in the other one too. I personally found the female leads pretty similar with their over-acting characters and tacky clothing. They're similar to the point I would think they're siblings.

Both involve competition in order to find the master chef, although Lady Iron Chef has more romance.

Both movies have a not-so-pretty female protagonist having a crush on the most popular guy in school. Both also have a long duration though I find Crazy Little Thing Called Love more dragging than Our Times. The last parts of Our Times reminded me of Crazy Little Thing Called Love and both films tackled the idea of innocent love.

The plot is very similar - they are both the aspiring artists who adopt a cat.

Both have similar set of actors and actresses. Nothing else beside that, but both are good in their respective genre

Both leads (the protagonist in NiF, the antagonist in Devil) use their enemy's dirty secrets and past deeds as their weapon to bring said enemy down while not actually doing anything besides setting the stage, thus not dirtying their own hand directly.

Only in The Devil the lead did what he did for pure revenge, while in NiF the lead did it to clean his family's name.

Similar plot about family not related by blood. I found Ugly Alert more touching though.

Even if the plots and the main characters are different, some characters appear in both dramas (in Faith they're young, while in The Great Seer they're older).
In both dramas there are supernatural powers (used to fight and to time-travel in the first, used for divination/geomancy in the second).

family of gangsters? i guess as soon as i read the plot i was reminded of bad family although i haven't watched the new drama yet but im kinda sure they will have the same vibe ^^