Those in Hufflepuff typically score higher in agreeableness and conscientiousness, reflecting the house values of loyalty and hard work.
Harry Potter and personality assessment: The utility of ... - PMC
Interestingly, individuals who self-identify as Slytherins or are sorted there often score higher on Dark Triad traits, including narcissism, Machiavellianism, and psychopathy.
An interesting paper related to your search for Harry Potter House backgrounds is by Laura Crysel et al..
If you're interested in how these traits manifest in real life,
Research found a strong positive association between those sorted into Ravenclaw and a high "need for cognition" —a psychological trait describing a person's enjoyment of effortful thinking.