One interesting scenario could be Harry having a conversation with the Whomping Willow. He could find out why it's so aggressive and maybe even convince it to be more friendly. Another could be him chatting with the house - elves through the rats or other small animals that might be in the kitchen. He could learn more about their secret world and their hopes and dreams.
One interesting scenario could be Harry using his snake - talking ability to communicate with a magical snake that guards a hidden treasure. The snake could lead him through a series of enchanted tunnels filled with various magical traps.
Well, he might be really confused at first. Fanfiction often takes the original story in different and sometimes wild directions. He could be shocked to see how some fans have imagined his relationships or new adventures that are quite different from his own experiences.
In some fanfictions, Harry Potter might learn some hidden secrets about the wizarding world's economy from the goblins. The goblins are known for their control over Gringotts and have a deep understanding of magical treasures. Harry could discover a new plot against Hogwarts related to a valuable artifact hidden in the vaults.
Maybe Harry discovers a new type of snake with magical abilities. For example, it could be a snake that can turn invisible at will. This would be really cool as it could add a new dimension to the wizarding world's magical creatures.
Perhaps Harry Potter talks to the dragon to enlist its help in finding a powerful magical object. Dragons are known to guard treasures. He could be on a quest for a Horcrux or some other important item. The dragon might initially be hostile but as they talk, it starts to trust Harry. Their conversation could involve exchanges about the power of magic, the dragon's own experiences in the magical world, and how they can both benefit from working together.
Well, he might try to tame the dragon. In some fanfictions, Harry could use his magic skills to communicate with the dragon on a deeper level, perhaps to gain its trust and make it an ally.
Perhaps a character accidentally transforms into the wrong Animagus form. Say Neville was supposed to transform into a small, unassuming animal like a mouse, but due to a spell mix - up or some magical interference, he turns into a large and clumsy hippogriff. He would then have to deal with not only being in the wrong form but also the chaos that such a large and not - so - subtle form would cause in Hogwarts, like knocking over furniture and scaring the other students.
Well, it could change the plot in many ways. For example, he might get early warnings about danger from animals. If a snake is about to attack someone in the Forbidden Forest, the snake could tell Harry, and he could prevent it. This would make him seem even more of a hero and might change the way his friends and enemies view him.
Well, he might be tempted by the dark magic within the Horcrux. It could try to manipulate him, maybe show him false visions of power or ways to defeat Voldemort that are actually leading him astray.
Imagine Harry being able to make plants sing. He could create a beautiful concert in the Hogwarts gardens with all the plants chiming in. Or he could use plants to create a floating garden in the sky above Hogwarts for a special event. Also, what if he uses his power to make plants that can detect lies? It would be a great help during interrogations or investigations.