In both series an arrogant, abusive and weird male lead of significant wealth, position and power is hideously treating a resourceful but childish female lead until she falls in love with him for no reason at all. All characters are nearing their 40s and are of course virgins and never had any prior romantic relationships. Really similar main couple dynamics.

Supernaturally long living characters wait for the reincarnation of their long lost love who sacrificed themselves to save them. Once found, they begin love-hate relationships with the reincarnation because it is a must to lift a curse. They will literally die from the curse if they don't. A lot of long stares and awkward moments. Both are BLs.

Century of love is about a girl reborn in male body, while Mr Queen is a man reborn in female one. Both of their love interests are oblivious about the situation and take time to establish a relationship although of course it's love from the first sight. Characters in both series have conflict about being attracted to the same sex. Despite a different plot otherwise, the gender identity and sexuality conflict is very similar, plus magic plot with a lot of clowning by secondary characters.

Both series explore the relationship between a gay and straight men, where gay character accepts their own sexuality and is willing to fall in love and form a wholesome relationship, while straight one has his doubts and internal conflict all the way through their relationship.
Both stories begin with straight character being clueless about gay man's sexuality and assumes that gay man should be very popular with women, since he is very good looking. Straight character is super unlucky with women.
Even after they clearly formed a very loving feelings towards each other and strated their relationship as a couple, straight character has troubles accepting the fact that he is with a gay man, of what people around think, and most of all the physicality of their relationship. Straight character avoids sex as much as possible, while gay character is very sexually active. Gay character is also very gentle and loving, while straight one is rough and rude, and offensive and many times unfair towards his partner and can't get past his internal conflict. Gay character is also very patient and super forgiving.

Innocent is a better made, more mature drama about violence and abuse, but main couple is a nice kind male lead and mentally unhealthy male lead who behaves like a toddler. Their relationship and physicality have a lot of similarities with Secret crush on you and leave equally unpleasant unsettling feeling.

Heartbeat is not a BL, but it has the same trope of vampire sleeping in a coffin for 100 years and vampires doing magic rituals to become human again. Also this retinue the main character has is even visually alike to that of Heartbeat main. Even the ridiculous haircut is similar.

Bl love story between the dentist and the patient. Very cute characters, a lot of shenanigans. Sweet tooth isn't even out yet, but it seems like a remake of My Tooth your love even judging by the trailer.

Same actors, same trope, almost same everything but with a ghost. After Sundown feels a bit underwhelming compared to Cutie Pie, because NuNew's character has no backstory, he is like a sheltered bride to be ready to become a wife and does all these household chores, that get pretty annoying pretty soon, unlike his character in Cutie pie where he has a whole accomplished career as a musician. Otherwise Zee is a husband who goes to adult male job and NuNew waits till he seduces him and they live happily ever after.

Cinematically beautiful, exceptionally well made, complicated enemies to lovers trope, clubs, underground, mafia, dubious concent, usage of illegal substances.