Master Chief's super - soldier abilities combined with Ryder's biotic powers would be extremely powerful. Chief's physical strength, combat training, and strategic thinking, along with Ryder's ability to manipulate mass effect fields, could create a character capable of taking on the toughest enemies. For example, Chief could provide cover fire while Ryder uses biotics to lift and throw enemies.
The Sangheili from Halo are known for their combat skills. If they were to team up with a Mass Effect Andromeda character like Drack, a Krogan with his own combat expertise, they could form a formidable duo. The Sangheili's agility and use of energy swords could be complemented by Drack's brute strength and combat experience. They could exchange combat techniques and develop new strategies for fighting enemies.
The UNSC Spartans' armor abilities and the technology of Mass Effect Andromeda could also combine in interesting ways. The Spartans' jetpacks could be enhanced with Mass Effect technology for more efficient flight. Their shields could be integrated with biotic barriers for added protection. And the Spartans' weapons could be modified to use Mass Effect ammo, increasing their firepower.
One aspect of Mass Effect Andromeda x Halo fanfiction could be the crossover of characters. Imagine Shepard from Mass Effect meeting Master Chief from Halo. Their leadership styles are different but both are highly respected in their respective universes. In fanfiction, they could team up to face a common threat that combines the enemies from both games, like a new type of alien that uses both the Reaper and Covenant technology. This would create a really exciting and unique story.
In a crossover, Kakashi could be an interesting character to combine with the Halo universe. His Sharingan allows him to use various jutsu. If he were in the Halo universe, he could use his teleportation jutsu in combat situations. He could also use his knowledge of different ninjutsu to create new strategies against the Halo enemies. And perhaps he could teach some of the UNSC soldiers how to better sense their surroundings, similar to how he uses his Sharingan in Naruto.
The Spartans' superhuman strength and advanced armor could be combined with GI Joe's stealth and infiltration skills. For example, a Spartan could provide cover fire while a GI Joe operative sneaks in to disable an enemy base's defenses.
Perhaps a crossover where the Covenant from Halo discovers the technology of the Milky Way species in Mass Effect Andromeda. This could lead to a power struggle as they attempt to either assimilate or destroy the new civilizations. The story could focus on how Ryder and his crew navigate this new intergalactic conflict while also trying to understand the motives of the Covenant.
The Covenant's energy weapons and their unique alien abilities could mix with the Star Wars technology and Force powers in various ways. The Grunts could be like the Ewoks in terms of being small but fierce when combined with the right support. The Elites' combat skills might be on par with some of the Star Wars bounty hunters, and together they could form an interesting team.
One popular trope is the 'fish out of water' scenario. For example, a character from Mass Effect Andromeda suddenly finding themselves in the Halo universe or vice versa. They have to adapt to the new rules, technology, and culture. Another common trope is the 'power - up' trope. A character might gain new abilities by combining the technology or powers from both universes, like using biotics with Spartan armor enhancements. And of course, the 'enemies to allies' trope is popular too, where the normally opposing forces in each game, like the Krogan and the Covenant, have to work together against a greater evil.
First, you need to be well - versed in both the Mass Effect Andromeda universe and the other universe you want to crossover with. Know the lore, the characters, and the rules of each. Then, start with a simple idea, like a character from one universe ending up in the other. For example, a Star Trek character landing in Andromeda. Build on that idea, think about how they would react to the new environment and the characters there.
The Asari from Mass Effect would be intrigued by the Ancient technology in Stargate. Their natural curiosity and long lifespan would make them eager to study it. Meanwhile, the Goa'uld from Stargate might see the various species in Mass Effect as potential hosts or slaves, which would obviously lead to conflict. But the more moral characters from Stargate would oppose this and try to protect the Mass Effect races.
If Tali met Naruto, she would be amazed at his ninja skills. Tali is used to advanced technology, but Naruto's physical abilities and unique jutsus would be a whole new concept for her. Naruto would be interested in Tali's engineering skills and might ask her to help create some new ninja tools. Garrus would probably respect Naruto's combat skills and see him as a valuable ally in a fight. And Naruto would be drawn to Garrus's sense of justice.
One interesting concept could be the crossover of different species from the Mass Effect universe in unexpected ways. For example, seeing Asari and Krogan working together in a completely new scenario that was not in the original games. Another could be the melding of Andromeda's technology with that of the Milky Way's in unique and creative ways, like a new type of weapon or ship design.