What categories of literature are found in the Old Testament?
In the Old Testament, there are many main genres accompanied by sub genres. If you put the Old Testament books into categories, you have the law/Torah/Pentateuch in the first five books. Then you have historical books, wisdom literature, poetry, major prophets, and minor prophets. These are the Christian categories of the books. The Hebrew Bible has only three categories of the books, Torah, Canticum, and Navi’im.
There are many sub genres within these major categories. For instance, many of the prophets use poetry to convey their message. Within the law books you have sub genres of commands, narrative, and priestly law.
Poetic books like the Psalms also have wisdom literature embedded in them. Within the Psalms also you have different types of Psalms like Psalms of lament, Royal Psalms, imprecatory Psalms, and many others.
So you can see there are many sub genres to the genres, the main categories of the Old Testament. I placed no more than five main categories of Old Testament literature. But the literature inside of these five categories is so rich that it defies having a simplistic view of the categories and genres of the Old Testament.