A very frequent theme is the comical aspect. The contrast between Thor's seriousness and baby Loki's mischievousness leads to many humorous situations. For instance, baby Loki might steal Thor's food or use his limited magic to play tricks on Thor, like changing his hair color.
One popular 'Thor and Baby Loki' fanfiction is 'The Adventures of Thor and Mini Loki'. It shows Thor taking care of a de - aged Loki and the humorous situations that arise. For example, Loki tries to use his magic in his baby form but ends up creating chaos in the Asgardian palace, like turning Thor's hammer into a plush toy.
There's 'Thor's Redemption in Loki's Arms'. In this story, Thor realizes his true feelings for Loki after a series of events that nearly tear Asgard apart. It's a tale full of emotion and character development.
Loki, on the other hand, might be in awe of Thor. He could look up to him as the ultimate hero. At the same time, he might also be a bit rebellious. Even as a baby, he could have that spark of mischief and try to break the rules Thor sets for his safety, which would lead to some comical or tense situations between them.
I really like 'A Different Path for Loki'. In this fanfiction, Loki is given a chance to redeem himself in a unique way. It's full of interesting plot twists and great dialogue between Thor and Loki. The author does a wonderful job of exploring Loki's psyche and his relationship with Thor against the backdrop of the Asgardian world.
If Loki survived in Infinity War fanfiction, it could have led to a very different outcome. He might have used his trickery to deceive Thanos in some way. Maybe he could have pretended to be on Thanos' side while actually working against him. This would have added an extra layer of intrigue to the story as the other characters would have been unsure of his true motives.
When Thor is mean to Loki in fanfiction, it can lead to a downward spiral in their relationship. Loki, feeling constantly attacked, may lash out in more extreme ways. Thor, on the other hand, may double down on his meanness, believing it's the only way to deal with Loki. This can create a cycle of animosity where any love or brotherly bond they had is overshadowed by anger and distrust. For example, Loki could start to form alliances with Thor's enemies out of spite, and Thor would see this as confirmation of Loki's untrustworthiness, making the relationship even worse.
Thor might initially go into denial. He can't believe that Loki is truly gone. He may hold Loki's body for a long time, as if waiting for him to come back to life. Then, he could become angry. Angry at the situation, at whoever or whatever caused Loki's death. Eventually, he may find solace in the memories of Loki. Remembering the good times they had together and using those memories to move forward.
These fanfictions typically show their relationship as something that has to be hidden from the rest of Asgard. It adds an element of secrecy and danger. The relationship is also often portrayed as a way for both characters to find solace in a world that doesn't always understand them. Loki's cunning and Thor's power are intertwined in a way that makes their connection unique and captivating.
In many Thor and Loki fanfictions, their brotherly love is often depicted through shared memories. For example, they might recall their childhood adventures in Asgard. These memories, both good and bad, are what bind them. Even when they're at odds, like in the movies, the fanfictions can dig deeper into the love that still exists beneath the surface. It could be shown through Loki's hidden loyalty to Thor, or Thor's unwavering belief in Loki's potential for good, despite all his misdeeds.