Another example is "Romeo and Juliet". Their relationship is a secret because of the feud between their families. They have to meet in secret and their love is ultimately a tragic one, but it is a very well - known story of a secret relationship.
The "Twilight" series can also be considered in a way. Bella and Edward's relationship has to be kept secret from most humans in the story because of Edward's vampire nature. It adds a layer of mystery and danger to their love story.
One popular "secret relationship novel" is "Pride and Prejudice". Mr. Darcy and Elizabeth Bennett have a sort of secret relationship at first. Their feelings are hidden beneath misunderstandings and social pretenses.
One popular 'secret identity novel' is 'The Strange Case of Dr. Jekyll and Mr. Hyde'. In this novel, Dr. Jekyll has a secret identity as the evil Mr. Hyde. Another example could be 'Superman' related novels where Clark Kent is Superman's secret identity. Also, 'The Invisible Man' can be considered in a way, as the man has a secret state of being invisible which he tries to keep hidden while going about his actions.
One example could be a wife who secretly volunteers at an animal shelter. She doesn't tell her husband at first because she wants to surprise him with a new family pet later. Another could be a wife who has a secret pen - pal relationship. She exchanges letters with an old friend from her childhood who she lost touch with, but she's not sure how her husband will react as he can be a bit jealous. There's also the case where a wife secretly takes art classes in the evenings. She's always wanted to explore her artistic side but was afraid her husband would think it was a waste of time.
There are quite a few. 'Me Before You' by Jojo Moyes has a relationship that is sort of a secret in the sense that Louisa and Will have a very personal and unexpected connection that develops over time. Also, 'The Fault in Our Stars' by John Green has a relationship between Hazel and Augustus that has a certain secrecy to it, as they are dealing with their own health issues privately while falling in love. 'Outlander' by Diana Gabaldon is another one. Claire's relationship with Jamie is full of secrets as she is from a different time period.
The mystery aspect. Fans are curious about the personal lives of BTS members, and a secret relationship in a fanfic satisfies that curiosity.
One example could be a story about a child secretly saving up money to buy a surprise gift for their mother. Another might be a person secretly learning a new language without telling anyone in order to surprise their friends when they can suddenly communicate in that language. A third example could be a group of friends secretly planning a picnic for another friend's birthday.
A true secret story could also be related to a historical event. During World War II, there were secret agents who worked undercover. One such agent managed to infiltrate the enemy's headquarters and steal important military plans. This agent's identity was kept a secret for many years to protect their safety and the success of the mission.
One example could be a special recipe that's only passed down within the family and made on certain holidays. For instance, my family has a secret cookie recipe that we only make at Christmas. Only the eldest women in the family know all the ingredients and the exact way to bake them.
One popular 'castaway novel' is 'Robinson Crusoe'. It tells the story of a man stranded on an island and his struggle for survival. Another could be 'The Swiss Family Robinson' which focuses on a family's adventures on a deserted island.
One popular 'beast novel' could be 'Beauty and the Beast' - the classic story where a young woman falls in love with a cursed beast. Another might be some fantasy novels where characters can transform into beasts. There are also novels in the werewolf genre that can be considered 'beast novels' as they deal with human - like beasts.
One positive example is when two students are in different majors but they support each other's academic pursuits. For instance, if one is in engineering and the other in literature. They can exchange different perspectives. The engineer can learn about creativity and storytelling from the literature major, and the literature major can gain logical thinking skills from the engineer. They attend each other's presentations and celebrate academic achievements together.