What are some possible plots in a 'Ben hears singing' fanfic?

Well, without more context about what 'Ben' is from (a movie, a TV show, a book etc.), it's a bit difficult to point out exact fanfics. However, if it's a relatively popular franchise, there are likely to be fan-created stories where a character named Ben hears singing. You might also check relevant fan communities on social media platforms. They often share and discuss good fanfics among themselves.

One possible plot could be that Chat Noir uses his singing to charm an enemy. He might sing a song that has some sort of magical effect, putting the bad guy in a trance or making them feel emotions that stop them from attacking.

One popular 'Ben hears Mal' fanfic could be 'Ben's Unheard Words' which delves into the unspoken thoughts Ben has when he's around Mal. It might explore his deeper feelings and how he perceives her in different situations.

A plot could involve a villain using the singing contest as a cover to steal a powerful ninja artifact. While everyone is focused on the contest, the villain is sneaking around. Also, it could be that a character who has always been shy about their singing talent finally decides to enter the contest after some encouragement from friends. As they progress through the contest, they grow in confidence and become a better ninja as well. And there could be a sub - plot about a love triangle that develops between characters during the course of the contest.

Maybe in the 'ben 10 hypnotized fanfic', Ben is hypnotized by a mysterious force during one of his adventures. As a result, he starts having strange dreams that seem real and he's unable to transform into his alien forms properly. His grandfather and Gwen try different methods, like using ancient spells or advanced Plumber technology, to snap him out of it.

One interesting plot could be Ben having to protect his vampire harem from other supernatural threats. Maybe a group of werewolves wants to drive the vampires out of their territory and Ben, with his alien powers, has to step in and defend them.

One interesting plot could be the characters from Ben 10 teaming up with Midnight to face a new and powerful alien threat that neither could handle alone. They might have to combine their unique abilities and strategies to defeat the enemy.

Well, in some fanfics, there could be a plot where an alien device causes Ben to have uncontrollable tickling powers and Rook is the main target. This creates a series of comical situations as Rook tries to avoid or deal with it. Also, a plot could involve the two of them getting into a tickle fight as a form of bonding after a particularly tough battle.

One interesting plot could be Ben traveling back in time to meet his younger self and having to hide his identity while trying to prevent a future disaster that his younger self unknowingly causes.

One possible plot could be that an interdimensional portal opens up and Ben 10 accidentally ends up in the Fairy Tail world. He then has to find a way back home while getting involved in the guild's problems. Maybe a powerful dark mage is after the Omnitrix, thinking it can give him ultimate power.