Hence, to investigate the categories of being is to determine what the most fundamental senses are in which things can be said to be. It is hoped, moreover, that a full account of the categories would be exhaustive in the sense that everything can be placed into at least one of the categories. Aristotle's particular list of categories is widely rejected nowadays, however, in part because the Aristotelian notion of substance has been widely rejected.
Philosophers have many differing views on what the fundamental categories of being are.
So a house is a being, a person's body is a being, a tree is a being, a cloud is a being, and so on. They are beings because, and in the sense that, they are physical objects. Each of us, according to common sense anyway, has a mind, a mind that exists or has being. So each of our minds is a being. Of course, philosophers rarely just assume that minds are a different category of beings from physical objects.