One of my personal favorite legend of zelda headcanons is that Lynels were either not always bestial monsters who would attack on sight (or can evolve to be an intelligent social race after being freed from Ganon's influence, but I like the deep lore of them having been corrupted by Ganon and being able to return to their previous state once he is gone).
They're already clearly very intelligent. They're the only enemy that can figure out you're not a Lynel when you're wearing the Lynel mask just by looking at you. They're able to fire an arrow up into the air and hit you even if you're standing behind an object that obscures you. They switch from ranged to melee weapons based on how far you are from them. It shows they have some reasoning abilities and even understanding of physics beyond a very base instinctual level.
I like to imagine that Lynels would still be largely solitary creatures in their uncorrupted state, sometimes moving about in small groups based in either family units or teams united for a common purpose. But maybe they did at one point in the very distant past have a homeland where they could congregate, perhaps outside Hyrule which is why it's unknown in the present.
I think they'd actually be very academic, and would travel a lot to study and document in their chosen field, hence the largely nomadic lifestyle. The combination of hardy hooves and dextrous hands would help them easily traverse places that would be impassible for normal hooved creatures and footed creatures alike. They are capable of feats of both great strength and delicate dexterity, and once produced great works of art.
Given the way they seek out very high, isolated places, astronomy may have been a common chosen field of study.
Their fall was concurrent with the beginning of the imprisoning war, which was the first time they were recorded appearing in Hyrule in official histories. They had previously traveled into the wilds of Hyrule, but any accounts made by people of the time were lost to the ages, and the accounts from the war only survived due to the fact that so many Lynels appeared together that they were witnessed by many people.
I like the idea of, after the events of ToTK, the Lynels regaining their full intelligence and appearing to speak to Zelda. Link immediately moves to attack but everyone is startled when the Lynel speaks. Zelda orders Link to stand down and gives him the chance to explain, and he does so and offers allyship of his people, who mean to reestablish a society outside of Hyrule. Zelda offers aid and they accept, and though all the races of Hyrule are extremely nervous about them, they start to interact and work together.
Also, in any story where a version of Ganondorf is saved, is able to return and be reformed, etc, the Lynels at first regard him as a mortal enemy for what he did to their people, and only eventually tolerate him if he proves he has changed (or, alternatively was corrupted by a being/force like Demise himself, in which case many Lynels actually turn around and accept him and mourn over what was done to all of them together).
I have so many fanfic ideas now, tbh.
