One way Loki could survive in a fanfiction of Avengers Infinity War is if he used his illusions more cleverly. He could have created a very convincing double of himself to be killed by Thanos while he escaped. Maybe he used his magic to teleport at the last moment to a hidden location in Asgard or even a different realm.
In fanfiction, Loki might survive if he made a deal with another powerful being. For example, he could have struck a bargain with an ancient magic entity. This entity could have shielded Loki from Thanos' attack in exchange for a future favor. Loki is known for his cunning and ability to manipulate situations to his advantage, so this would be in character for him. Also, he could have faked his death by using his shape - shifting abilities combined with some powerful Asgardian artifacts that can mask his life force.
The plot could start with Loki's clever escape. He then realizes that he needs to find a way to stop Thanos on his own. Loki could travel to different realms to gather allies. He might convince the Frost Giants, his own people, to join forces with the other heroes against Thanos. Along the way, he discovers a hidden power within himself that was unlocked by his near - death experience. This new power gives him an edge in the fight against Thanos.
One way Loki could survive Infinity War in fanfiction is through his shape - shifting abilities. He could have faked his own death by creating an illusion of himself being killed by Thanos while he actually slipped away. Another possibility is that Heimdall, using the last of his power, sent Loki to a hidden realm before Thanos could deal the fatal blow.
A possible plot twist could be that Loki was actually working with Thanos all along, but faked his death to deceive the Avengers. This would change the whole dynamic of the story and lead to a new set of conflicts. Another twist could be that Loki's survival was part of a grand plan by Odin (who might not be truly dead) to stop Thanos from getting all the Infinity Stones.
Another aspect could be Loki's relationship with the other characters. Without Thor, he would need to build new alliances. He could form an unexpected bond with Hulk, perhaps using Hulk's brute strength and his own cunning to create a unique duo. They could then set out on a mission to retrieve the Infinity Stones from Thanos, with Loki devising elaborate plans and Hulk providing the muscle.
Loki could gain the ability to harness Thor's lightning. Maybe in the moment of Thor's death, some of his power transfers to Loki. This would be a huge boost to Loki's combat abilities and could make him a more formidable opponent against the likes of Thanos.
In a fanfiction scenario, Yondu might survive Infinity War if he had some sort of hidden power or ability that was never explored in the movies. For example, he could have a latent connection to the Soul Stone that shields him from Thanos' snap. This would not only save his life but also give him a new purpose and arc within the Infinity War story.
Loki's survival might also lead to a shift in power dynamics. In the Asgardian remnants, he could emerge as a leader figure, using his wits and magic to protect and guide them. This would change the way Asgardians are perceived in the MCU. Instead of being a broken and defeated people, they could become a force to be reckoned with under Loki's leadership.
Another plot could focus on Thor. After losing so much in Infinity War, he might become a bit of a recluse. But then he realizes that he has a responsibility to the remaining Asgardians and the universe. So he starts to gather the remaining heroes and form a new plan to fight against the consequences of Thanos' snap.
In Infinity War fanfiction, Loki can be alive. Fanfic authors have the creative liberty to rewrite the events. They might bring Loki back to life using magic or some other means. For example, Loki could have faked his death and gone into hiding, only to reappear later in the story to help the heroes fight against Thanos. His survival can add an interesting twist to the story and create new interactions between characters.
A plot might also revolve around the villains. Some villains might see the chaos as an opportunity to take over. The Avengers would then have to deal with new threats while still recovering from the events of Infinity War. The fanfic could show how they come up with new strategies and alliances to face these challenges.