I lol'd at illiterate weeaboos frantically suggesting magical schools as soon as they see "Harry Potter"

It's certainly a fresh type of request. Most manga with protagonists that are "special" in some way start out normal but gradually work their way up the chain, eventually finding out they they have all this potential to become very, special. Or, they're special from the start and already have their work cut out for them because of their higher status. It's a very Japanese trope.

It's not common for protagonists to be born special but simply not know about it. The whole "preordained destiny" trope is more common in the West, it seems. And then the protagonist must decide whether to make their own fate, or follow their destiny, etc...

Anyway, regarding your request I don't have much to offer because as I haven't read much else fitting your criteria that hasn't been mentioned in this thread already.

On the topic of shounen, one of the first things that comes to mind is Bleach, because it does fit. But then again, it's Bleach...

Dragon Ball, when the story arc changes to adult Goku (basically from the DBZ anime onwards)

To Aru Majutsu no Index. The light novel is the way to go because it's so detailed and so many volumes are already out, but if Japanese is a problem, you could read the scanlated manga or watch the animated series. (anime sucks compared to the novel, IMO)
The spinoff, to Aru Kagaku no Choudenjibou, is about someone else who's special from the start. Cool, but not really what you're looking for.

Kaze no Stigma (novel) light novels are good. The first 3 novels or so are already translated, and there are currently 12 out. The story is unfinished, though, because the author passed away last year 🙁 There are also a manga and a mediocre anime out, too, but I wouldn't bother with them unless you really like the novels (I did).

Let's see, what else... Moses in Bible's book of Exodus? It's true! ahahahah

Hunter x Hunter might fit your criteria.
Gon was raised on a remote island by his aunt & grandmother (but they treated him very well). He learns his father was a 'Hunter' (person of elite abilities), and decides to follow in his footsteps.

Another might be Psycho Busters. An 'ordinary' boy falls in with a group of psychic teens. But they think he's has a talent too. So is he really ordinary?

Quote from mewarmo990

Let's see, what else... Moses in Bible's book of Exodus? It's true! ahahahah

You don't need to laugh, I loved The Prince of Egypt movie when I was a child 🙂

And again, thanks for recommendations 🙂

No problem.

And yeah, as the poster above said, Hunter x Hunter fits your expectations. Secret lineage backstory and everything.

Haha, I had a nice laugh at all the fools suggesting magical school mangas.

Anyway, Global Garden fits perfectly. It's a shoujo with not very much adventuring, so I'm not sure if it's exactly what you're looking for, but the main character is basically treated like crap by her own mother. She pretends to be her dead twin brother because her mom apparently loved him more and is a little crazy. Turns out the girl has some sort of amazing destiny or something.

Also maybe Genjuu no Seiza. I don't think he's particularly mistreated, but as the summary says: "Kamishina Fuuto would like to think he's a normal boy, but he is the reincarnation of the High Priest of Darashaal"

I know I thought of another one but it slipped my mind.

Threads of Time

Shade: The Other Side of Light

Tegami Bachi

Zombie-Loan

Monk!

Shingetsutan Tsukihime

And, I think the first season of Digimon would work as well... because I remember the children were prophesied to enter the world and save it. Of course, it's been a while... and my memory might be faulty.

[color=green]"Officially, this machine doesn't exist, you didn't get it from me,
and I don't know you. Make sure it doesn't leave the building."[/color]