The world of The Legend of Zelda has always been characterised by a multitude of races and character types with their own unique appearance, habitat and customs.
Well, while Breath of the Wild is arguably the most complete game in the series, there are many of these races that were not present in the open-world game. So it stands to reason that many of these will be in the sequel, which is coming to Nintendo Switch in 2022. One such race would be the Uca, the bird-like, humanoid beings that live in the skies, first seen in Twilight Princess. Their appearance would make a lot of sense in the sequel to Breath of the Wild due to the relevance of the sky in this new adventure.
Finally, another possibility would be the appearance of the Zonnan, a tribe whose existence is reflected in Breath of the Wild in the different monuments we can see in the so-called Zonnan Ruins, although no one of that species made an appearance in the game.