Major or Minor, the vast majority of the Old Testament prophetic text is made up of visions, oracles or messages from God through the prophets to individuals or nations. There are exceptions, of course. Isaiah contains a historic interlude or two, as do Haggai, Daniel, Ezekiel, Jonah and especially Jeremiah, who provides an exceptional amount of useful historical context.
In addition to the history, some prophets also recorded the personal instructions, special insights, correction or encouragement God gave them in the process of serving him, and the substance of their conversations and interactions with him. Jonah does this in every chapter.
But no prophet preserved more of God’s editorial commentary on his own messages than Jeremiah, all the way through the first 2/3 of his prophecy.