Well, in some fanfictions, when they meet again, Sasuke and Sakura could go on an adventure together. They might face new enemies and in the process, rekindle their relationship. Sasuke could show his protective side for Sakura more than ever, and Sakura would be there to support Sasuke both emotionally and in battle.
When Sasuke and Sakura meet again in fanfiction, it could be a very emotional moment. Sakura might be initially hesitant, given their past. But Sasuke could take the lead and try to make amends for his past actions. They could then start to build a new relationship, perhaps even starting a family in some fanfiction scenarios. There could also be some action - like they team up to fight a common foe, which brings them closer together as they rely on each other's skills.
They might have a really emotional reunion. Percy could give Annabeth a big, warm hug and they'd start reminiscing about their past adventures together, like the time they were in the Labyrinth or on their quests.
They might go on a new adventure together. Maybe they'll discover a rare Pokémon that neither has seen before and team up to catch it, just like the old days.
They might immediately embrace and share all the adventures they had separately. Gendry could show Arya the new skills he has learned, like advanced blacksmithing techniques. And Arya might tell Gendry about the different places she has been and the people she has met on her journey.
They might have an intense emotional reunion. Edward could be overcome with joy and relief at seeing Bella again. Maybe he'll take her into his arms immediately and they'll just stare into each other's eyes, all the past feelings flooding back.
Well, perhaps in this fanfiction encounter, Rowle has changed. He could approach Hermione with an offer of truce or alliance. Maybe he has seen the error of his ways in the dark wizarding world. Hermione, being the intelligent and cautious witch she is, would be very skeptical at first but might listen to what he has to say.
They might have a warm embrace. Haku could show Chihiro all the new and beautiful parts of the spirit world that have emerged since she left. They could share stories of their time apart, with Haku telling Chihiro about how he has been protecting the spirit world and Chihiro sharing about her life in the human world.
They might have an epic battle to test Luffy's growth. Shanks could see how much stronger Luffy has become and be proud. Maybe Luffy will show off his new Haki abilities.
In fanfiction, when Ash and Serena meet again, they might share a warm embrace. Maybe Serena has new Pokémon skills to show Ash. They could also start a new adventure together, exploring uncharted regions and facing powerful new opponents.
In fanfiction, when Sabo and Luffy meet again, they might have an emotional reunion. They could share stories of their adventures since they last saw each other. Sabo might show off his new skills or powers, and Luffy would be excited to see his brother again. They could also plan new adventures together, vowing to face any challenges as a team.
They might finally make peace. In many fanfictions, Dudley has grown and realized how wrongly he treated Harry in the past. So when they meet again, they could start to have a normal conversation, maybe even become friends or at least be civil to each other.