For some actually interesting research on human brains, even if from over 20 years ago, see https://doi.org/10.1093/brain/123.1.74 – most right-handed people activate left hemisphere brain regions during language processing, but approximately 7.5% of them activate right hemisphere brain regions instead. Their brains (or at least this aspect of them) are "swapped" compared to the majority of the population.

I find that fascinating as an example of genuine biological neurodiversity, with no known clinical significance. There is a lot of talk of "neurodiversity" nowadays, but it is neurodiversity assumed to exist based on observable differences in people's behaviour or the assignment of a clinical diagnosis – and not everyone with certain behavioural traits gets the diagnosis, since the process of diagnosis is heavily influenced by social and cultural factos – and in most cases with no identifiable neurobiological difference in any particular individual. All the people in this study were "neurotypical" – they had no known diagnosis of any psychiatric or neurodevelopmental disorder – and yet 7.5% of them were actually neurodiverse in this particular way, and I imagine if you looked for other forms of biological neurodiversity too and added them all up, you might reach the conclusion that "neurotypical" people don't really exist and at the biological level everyone is neurodiverse.