A great 'Avengers meet Loki' fanfiction could involve time travel. Loki somehow gets sent back in time and meets the younger versions of the Avengers. This throws the timeline into chaos as Loki has the knowledge of future events. The Avengers, being the heroes they are, have to work with Loki to set things right. There would be a lot of interesting interactions as the young Avengers react to Loki's presence and his knowledge of their future selves.
There might be a fanfiction where Loki gets amnesia and the Avengers find him. They don't believe it at first, but as they try to figure out what happened to him, they start to see a different side of Loki. He begins to form bonds with some of the Avengers members, especially Thor who is desperate to get his brother back. This could lead to a series of adventures where Loki is trying to rediscover himself while the Avengers are trying to decide if they can trust him.
One interesting 'Avengers meet Loki' fanfiction could be where Loki is actually forced to team up with the Avengers against a greater threat. Maybe a new, powerful enemy emerges that Loki realizes he can't defeat alone, and he has to use his wits and the Avengers' strength. In this story, there could be a lot of humorous exchanges as the Avengers are initially very suspicious of Loki.
In some 'Avengers and baby Loki' fanfictions, baby Loki could form a special bond with one of the Avengers, like Thor. Thor might be extra protective of his younger self in a way and try to shield baby Loki from the more judgmental Avengers while also teaching him about their family's history.
A major theme is power. Kid Loki is always in search of power, whether it's to prove himself or for more devious reasons. In 'Avengers meet Kid Loki' fanfictions, this power - seeking is often juxtaposed with the Avengers' use of power for good. Another theme is friendship. Kid Loki forms unlikely friendships with some of the Avengers. For instance, he might bond with Hulk over their shared sense of being outsiders in a way. And the theme of discovery is also there, as Kid Loki discovers new things about himself and the world around him through his encounters with the Avengers.
In some fanfictions, Sigyn might be brought to Earth by accident and the Avengers initially mistake her for a threat. But as they get to know her, they realize she can be a great ally. For example, she could have the ability to heal some of the Avengers' wounds that normal medicine can't. And she might also introduce them to some Asgardian technology or magic that they can use in their future battles.
One possible plotline could be that future Loki comes with a warning about a new threat that the Avengers initially don't believe. For example, he might tell them about a powerful being from another dimension that is slowly making its way to Earth. Another plotline could involve future Loki trying to redeem himself in the eyes of the Avengers by helping them prevent a disaster that he was partly responsible for in his own timeline. He could use his knowledge of magic and trickery to outwit the new enemy.
One popular 'Loki Saves Avengers' fanfiction might involve Loki using his trickery in a unique way to rescue the Avengers from a powerful enemy. For example, he could deceive an evil force into thinking the Avengers are in one location while secretly leading them to safety.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions, and you can use the search function to specifically look for 'Avengers meet Loki' stories. There are often filters you can use to sort by popularity, rating, etc.
The fanfictions are interesting due to the potential for unique plot twists. Loki's complex personality and his array of magical powers allow for many different scenarios where he can save the Avengers in unexpected ways. For instance, he could use his illusions to deceive the enemy, or his knowledge of other realms to find a solution to a problem that the Avengers can't solve on their own. Also, the dynamic between Loki and the Avengers, who have been his foes, changes dramatically, creating a lot of tension and character - based drama.
One popular 'Avengers Loki Punishment' fanfiction might involve Loki being banished to a desolate realm as punishment. In this scenario, he has to face the harsh conditions alone and reflect on his misdeeds. This could be a way for the Avengers to teach him a lesson without actually harming him physically but still making him endure the consequences of his actions.
In some fanfictions, fem Harry Potter could end up training with the Avengers. Maybe Black Widow takes her under her wing to teach her combat skills, while Thor tries to understand the nature of her magic. This could lead to a lot of character development for fem Harry Potter as she learns new ways of fighting and the Avengers learn more about the magic that exists in her world. It would be a great blend of two very different universes.
Well, 'Quicksilver in the Avengers' World' is a really interesting fanfiction. It starts with Quicksilver suddenly appearing in the middle of an Avengers' battle. His speed throws the enemies off balance as the Avengers are both surprised and impressed. There's also 'Avengers: Meeting Quicksilver'. This one delves into the relationships that form between Quicksilver and the individual Avengers. For example, his friendly banter with Iron Man about who is faster - Quicksilver's legs or Iron Man's suit. And 'The Arrival of Quicksilver to the Avengers' shows how Quicksilver's powers can be a game - changer for the team.