Curate, connect, and discover
I feel like I shouldn't be allowed to say much of this Fandom since I'm not a big fan of it (not that I'm not not a fan) but here I go.
Headcanon theory thing: If Harry were to have an animagus, I would think it to be a mouse.
Why? Why on Earth of all things a mouse?
There are a few reasons why:
They're small. They can hide in small spaces and remain unseen. Harry's used to being crammed in small spaces and though he doesn't have to go through that anymore it does help him escape the large group of reporters that try to follow him.
He learns to love what he hated. He hated it, despised using his animagus at first. Hermione and Ron did try to convince him (half-heartedly) to try to understand it but he just wouldn't. Until he found himself using it when it was just too crowded for the invisible cloak. So it was a little more acceptable to use it but only in emergencies. But I like to think over time he learns more about his animagus and loves it because even though it reminds him of the traitor who killed his family (though he was a rat not a mouse), it also gives him more freedom.
Mione and Ron. If they had an animagus it would be an African Grey (yes I was very specific about this) and a weasel (I know I know, rather mean of me). Like the Marauders, they would sometimes go out and adventure around in nature in their animagus forms. (Sometimes even flying with Hermione if she could handle it)
Not much of a headcanon/theory is it? But i think I did what I could.