Well, the concept of good versus evil in a new context is a common theme. When 'Despicable Me' crosses with 'Batman', Gru and his family might have to decide whether to side with Batman or the Joker. Another theme is family dynamics in a different setting. In a crossover with 'The Loud House', the large family of 'The Loud House' contrasts with Gru's family, and they learn from each other. Also, the theme of discovery is often present. In a crossover with 'Journey to the Center of the Earth', the characters from 'Despicable Me' discover new lands and creatures, and the Minions get into all sorts of trouble during the exploration.
A prevalent theme in 'Despicable Me Crossover Fanfiction' is the exploration of new powers or abilities. In a crossover with 'The Avengers', the Minions might gain superpowers and have to figure out how to use them. Another theme is the adaptation to new environments. When crossing over with 'Avatar', the characters from 'Despicable Me' have to deal with the unique flora and fauna of Pandora. And cultural differences are also a common theme. For instance, in a crossover with 'Aladdin', the different cultural norms between Agrabah and Gru's world are highlighted through the characters' interactions.
Occasionally, there are fanfictions that revolve around holidays. For instance, how they celebrate Christmas or Halloween in the 'Despicable Me' world. These stories usually show their fun and festive side, with lots of Minion - related chaos and cute moments with the girls.
Greed is also a typical theme. In many despicable life stories, people are driven by their greed to take advantage of others. For example, a landlord who overcharges a poor tenant just to make more money is being greedy and acting despicably. And then there is dishonesty. Lying, cheating, and stealing are all part of the dishonesty that often shows up in these stories.
A common theme is the struggle for acceptance. The minotaur, being a different and often feared creature, usually has to fight to be accepted in the new world or by the new group of characters it crosses over with.
One common theme is power struggles. Since there are different powerful characters from various planes, they often clash over control or resources. For example, in many fanfictions, two powerful planeswalkers might fight for dominance over a newly discovered plane.
Power is a common theme. Since Vegeta is extremely powerful, seeing how his power compares to characters from other universes is always interesting. Another theme is culture clash. For instance, when Vegeta enters the Harry Potter world, his Saiyan warrior culture clashes with the wizarding culture. Pride is also a theme. Vegeta's Saiyan pride often plays a role in how he interacts with characters from other fandoms.
Survival is also a big theme. Characters in the crossover fanfiction usually have to figure out how to survive in the presence of Annabelle, especially if they come from a world where they're not used to such malevolent supernatural forces.
One common theme is the idea of redemption. Raphael, who has a somewhat dark past in the original lore, often goes through a journey of redemption in these crossovers, especially with Simon's influence. Another theme is friendship. Despite their differences, they form a strong bond.
Another theme is power exploration. Naruto and Sakura have their own set of powers from the Naruto universe. When they are in a crossover, they often have to figure out how their powers work in relation to the new world they are in. This can lead to some really interesting battles and power - up moments as they learn to adapt and use their skills in new ways.
The theme of redemption also shows up sometimes. Despite being a fearsome character, in some crossovers, Deathwing might be given a chance to redeem himself. Maybe he caused a lot of destruction in his original world, but in the crossover world, he has the opportunity to do good deeds and change his reputation.
One common theme is power exploration. Writers often explore how Tsuna's powers interact with the powers in the crossover universe. For example, in a crossover with a superhero universe, how Tsuna's unique abilities compare to superpowers like flight or super strength.