Perhaps in this fanfiction, Harry's relationship with the wizarding world at large is very different. Since the Unspeakables are quite secretive, he may be seen as an enigma. He could be involved in solving mysteries that are related to the deepest secrets of the Ministry of Magic, which normal wizards are not even aware of.
Another possible plot is that his upbringing by the Unspeakables gives him a unique set of skills and knowledge. He might be able to communicate with magical creatures in ways that others can't, or have a deeper understanding of the history and origin of magic. This could lead to him having adventures that are far removed from the typical Hogwarts - centered ones in the original books.
His character may become more reserved. Growing up with the Unspeakables, who deal with secret and often dangerous magic, he would learn to keep his thoughts and actions guarded. He might not be as quick to trust others as he was in the original series.
Well, perhaps a plot where Harry has to defend the bears from dark wizards who want to harm them for some reason. Since he was raised by bears, he would have a deep connection with them and would do anything to protect them. He might use his unique knowledge of the forest, gained from living with the bears, to outwit the dark wizards.
Perhaps in this fanfiction, the scorpion - raised Harry has a very different relationship with Hogwarts. He might be more of an outcast due to his strange upbringing, and has to fight harder to prove himself worthy of being at the school. His knowledge of the wizarding world might be different too, as the scorpion may have taught him some unorthodox ways of using magic.
Well, in some of these fanfictions, Harry might be raised with a different set of values. Maybe he becomes more attuned to a certain magical aspect that was overlooked in the original series. For example, he could have a stronger connection to magical creatures if his 'rq' upbringing emphasizes that.
Well, in some fanfictions of this kind, Harry might learn magic in a completely different way because of being raised by snakes. Maybe the snakes teach him ancient and forgotten spells that are not known to the regular wizarding community. Also, his personality could be more aloof or mysterious due to his upbringing. He could have a different set of friends, perhaps those who are more interested in the dark arts or the secrets that snakes seem to hold.
One interesting plot could be Harry being raised by a pack of wolves. He might learn their ways of survival, like hunting and communicating through howls. This would give him a very different set of skills compared to his wizarding upbringing in the original series.
One interesting plot could be Harry developing unique magical abilities due to his upbringing among spiders. For example, he might be able to communicate with spiders in a more profound way than just Parseltongue, and use this to his advantage in dangerous situations.
Well, one possible interesting plot could be how Harry's magic develops in a different way under the influence of the Veela. Maybe his spells have a unique flair or he has an enhanced connection to certain types of magic. Another plot could involve the Veela's culture and how Harry adapts to it while growing up. For example, their social norms and traditions might shape his view of the wizarding world.
One interesting plot could be that the OC (original character) has a unique magical ability that they pass on to Harry. For example, the OC might be able to communicate with magical creatures in a way no one else can, and they teach Harry this skill. This could lead to Harry having a whole new set of allies in the magical world.
There could be a plot where Harry's upbringing at Hogwarts affects his relationship with the other students. He might be seen as an insider by some, but also an oddity by others. This could lead to some interesting dynamics, such as rivalries or unexpected friendships. For example, he might have a closer friendship with the students from different houses as he doesn't have the same house - based prejudices that other students have.