A popular trope is the 'time - travel' one. The male reader travels back in time in the Naruto world and tries to change certain events. Then there's the 'secret identity' trope. He could be hiding his true power or identity from others in the village. And the 'team - up' trope is also well - liked. He teams up with Naruto, Sakura and others to face a common enemy, like Orochimaru or Pain.
In Pokemon X Male Reader fanfiction, the 'Lost in a New World' trope is often seen. The male reader is somehow transported to the Pokemon world and has to adapt. The 'Power of Friendship' trope is also prevalent, emphasizing how the male reader's relationships with his Pokemon and other trainers are crucial. Another trope is 'Redemption Arc', where a previously antagonist character or Pokemon is redeemed through the male reader's influence.
One popular trope is the 'underestimated male reader' who turns out to be really powerful in the Duel Monsters world. Another is the'male reader as a new student at the Duel School' and getting involved in all kinds of adventures and duels. And of course, there's the 'romantic subplot' where the male reader has a relationship with one of the characters from the show, like Yuya or one of his friends.
The 'Forbidden Love' trope is quite popular. Maybe Robin is from a different group or has a secret that makes the relationship with the reader seem impossible at first. It adds a lot of drama.
One popular trope is the 'powerful reader' where the inserted character has some unique or hidden power. For example, they might be able to control a new type of spiritual energy. Another is the 'romantic insert' where the reader - insert character gets involved in a romantic relationship with one of the main Bleach characters, like Ichigo or Rukia. And the 'mysterious origin' trope is also common, where the reader - insert's past is shrouded in mystery and slowly revealed throughout the story.
One common trope is the 'stranger in Middle - earth' where the reader is from our world and somehow ends up in Middle - earth and meets Bilbo. Another is the 'unlikely pair' trope as Bilbo is a hobbit and the reader is usually a human or some other being, so their relationship is seen as an unlikely but interesting one.
One popular trope is the 'Redemption Arc' for Konan. In many fanfictions, Naruto helps Konan move past her dark past with Akatsuki. For example, in some stories, he shows her the true meaning of peace, and she starts to fight for a better world.
One popular trope is the 'fish out of water' scenario. Hellboy suddenly finds himself in Naruto's world full of ninjas and strange customs, or vice versa. Another is the 'team - up against a greater evil'. They have to combine their powers and skills to defeat a powerful foe. The 'culture clash' trope is also common. Naruto's positive and energetic ninja culture clashes with Hellboy's more somber and dark world view.
One popular trope is the 'Enemy to Allies' trope. Since Scorpion is from the Akatsuki and Naruto is a Konoha ninja, they start as enemies. Fanfictions often explore how they can put aside their differences and work together. It adds a lot of drama and tension.
One popular trope is the mentor - mentee relationship. Tsunade often acts as a mentor to Naruto, guiding him in areas like control over his power or in understanding the politics of the village. Another is the adventure trope, where they go on an adventure together, facing various enemies and obstacles along the way.
One popular theme is power - acquisition. Many fanfictions focus on the male reader character obtaining unique powers and using them in the Naruto world. Another is friendship. Stories often explore how the male reader forms strong bonds with Naruto and his friends.