Both have MLs who have a crush on their friend who dates a ton of girls in school but never gets serious with any of them.

Both are youth dramas in which the FL is childhood friends and in love with the ML who ends up getting into trouble over and over. Meanwhile another boy moves into her street and begins being kind to her and eventually becomes the endgame.

Both MLs are wealthy CEOs with severe personality issues who are controlling and possessive toward the FL who finds herself swept up in dangerous events regarding his/her family.

Both MLs are royal generals who position is viewed as a threat by the court, despite him having no interest in the throne, and the court tries to prevent him from marrying or having children. TSPL ends happily, OAO tragically.

Both FLs are the unfavored/not permitted daughter of a family who take the place of their sister in an arranged marriage. Both MLs start out cold and suspicious but quickly fall in love.

Both FLs are unfavored princesses who enter into an arranged marriage with a general. Both MLs are distrusting and cold toward the FL at first but then fall deeply in love.

Both MLs are generals who the FL are forced into a marriage with, but the two fall in love. TSPL is purely historical, whereas TLWOTG has transmigration/time travel.

Both involve time travel in which the leads' timelines flow at different speeds, so one is going back further in time while the other is moving forward.

Both have supernatural, grim reaper like figures overseeing and existing amongst humans and guiding them in their memories and deaths. Both have love story between a lead that's a doctor and the other that's a grim reaper or similar sort of figure.

Both have supernatural, grim reaper like figures overseeing and existing amongst humans and guiding them in their memories and deaths.

Both are short length dramas with similar vibes and supernatural, powerful beings overseeing human lives.

Both are about the FL traveling from the real world into a fictional one where she meets the ML. Both couples are magically connected for a time, and both MLs were intended to be sacrifices, but survived because their families died protecting them.