One possibility is that they become friends immediately. The elf could be really friendly and show Harry around the elf village or something. Another is that they start off on the wrong foot. Maybe Harry accidentally offends the elf at first, but then they work through it.
Another interaction could be them collaborating on a project. Maybe they are in a situation where they need to build something or solve a mystery. Annabeth's strategic thinking combined with Estelle's fresh perspective could lead to an interesting and successful partnership.
Perhaps they go on a family trip. During the trip, Pan might see something amazing like a rare animal or a beautiful waterfall. She'd run to tell Gohan and Videl, and they'd all share in the joy of the discovery. They could also have conversations around the campfire at night, with Pan asking about their past adventures and Gohan and Videl happily sharing their stories.
Naruto could get hugs from the Hokages. The First Hokage might pat him on the back and praise his strength. The Second Hokage could quiz him on his ninja knowledge. The Third Hokage would probably give him a warm smile and some encouraging words. And the Fourth Hokage would hold him tight, with tears in his eyes.
In some fanfictions, Snape might save Harry from a dangerous situation. For instance, if there's a new dark wizard threat in Hogwarts, Snape could use his skills and knowledge to protect Harry. This would show a positive side of their relationship as Snape is putting Harry's safety first.
One possible positive interaction could be Narcissa helping Hermione understand some of the pure - blood wizarding traditions in a more in - depth way. Since Narcissa is from a pure - blood family, she has a lot of knowledge about it. Another could be Hermione using her logical thinking to help Narcissa out of a difficult situation, like a tricky political problem in the wizarding world.
They might have a friendly competition. For example, who can solve a time - related mystery faster.
Luffy might have an interesting interaction with Superboy. Superboy's struggle with his identity and Luffy's unwavering self - confidence could create a contrast. Luffy could encourage Superboy to be more true to himself.
There could be themes related to loyalty and trust. Since elves are often seen as very loyal in the Harry Potter universe, Harry in this role might have to re - evaluate his loyalty to Severus and vice versa. Also, there could be a theme of transformation, not just in the physical sense of Harry being an elf, but also in his character as he adapts to this submissive role. It could be about breaking down his usual heroic and independent image and building something new. This could lead to some interesting character development and interactions between the two characters.
Naruto could be really enthusiastic and make the poker game more lively. Kurenai would likely be the voice of reason. Anko might try to tease Naruto during the game. For example, Naruto makes a big bet and Anko says something like 'You think you can win that easily, do you, Naruto?' Kurenai would then step in to keep the peace and focus on the game.
A more intense interaction could be a fight. Maybe there's some misunderstanding or a power struggle within the mansion. Rogue might accidentally absorb some of Wolverine's memories or emotions, which could make him angry. This could lead to a physical confrontation between them, but in the end, they would probably resolve their differences and come to a better understanding of each other.