Flora and fauna are two different categories of living things; traditionally, people use these words to distinguish one type of life from the other (even though there are life forms that don’t fit into either category, like fungi).
You might be thinking of the categories “animal, vegetable, mineral”, which are traditionally used to categorize types of things that are alive from things that are not.
But we don’t tend to say “flora, fauna, mineral” or to use any word describing things that are not alive in juxtaposition with the words “flora” and “fauna”.