These dramas are very similar in that they both revolve around the stories of couples in the same building. They both also include a gay couple. However, Tonari no Kazoku wa Aoku Mieru does not have much of a comedy elements.
These both involve a chaebol family losing a child, those children being raised in average/poor families, and finally returning to their birth families.
These are both family dramas and focus on marriage and different married couples. They both also have Choi Dae Chul.
Both dramas have a married couple who goes through a divorce. They both also have a couple trying to get married.
Eulachacha Waikiki and Twenty are both centered around friendship and brotherhood. Both are also very funny and contain a romance aspect.
Both female leads see supernatural beings. They also both involve possession. The dramas also have a good comedy aspect along with the romance.
Both dramas involve a supernatural/ fantasy aspect. There is a ghost in Chicago Typewriter and demons/ deities/ spirits in A Korean Odyssey. There are also a few scenes of the Japanese occupation in A Korean Odyssey. Both dramas also have a similar feeling and tone when you watch them.
Both dramas circle around the relationships of a group of friends. However, age of youth focuses more on friendship and Because This Is My First Life focuses on romance.
Both are about close friendship and how those friends experience relationships, college, and life in general.
Both dramas include a contract relationship but end up falling in love. Both dramas are also pretty short and good weekend watch.
Boku no Ita Jikan and Sky of Love (Koizora) both show how one of the character's illness affects their relationship.
Both dramas contain a supernatural aspect. and the main leads are “possessed” in some way. In Black, the main character’s body is possessed by a grim reaper; in Oh My Ghostess, the main character is possessed by a ghost. Both also have crime/ thriller aspect, but Black is much darker than Oh My Ghostess.