Proverbs
Proverbs isn't a random collection of fortune cookies, but a carefully curated wisdom manual.
Structurally, you can divide the book into seven sections, using the text itself as the marker:
"The Proverbs of Solomon son of David, king of Israel." (Prov 1:1) — Long form. Father-to-son essays with interludes by Lady Wisdom.
"The Proverbs of Solomon" (Prov 10:1) — Individual couplets. Chapters 10-15 are dominated by antithetical parallelism (righteous/wicked, wise/foolish as contrasting pairs) while chapters 16-22 shift toward synthetic parallelism. Also Yahweh sayings cluster noticeably in chapters 15-16.
"The Words of the Wise" (Prov 22:17 — Mixed length. Has a notable connection to the Egyptian Wisdom of Amenemope.
"These also are of the Wise" (Prov 24:23) — Mixed length. A continuation of the previous section.
"These also are Proverbs of Solomon, which the men of Hezekiah copied out" (Prov 25:1) — Individual couplets. The Hezekiah collection. Noticeably more simile-based than section 2.
"The Words of Agur son of Jakeh" (Prov 30:1) — Long form.
"The Words of Lemuel, king of Massa" (Prov 31:1) — Long form. Includes the acrostic poem "Proverbs 31 Woman".
Note the symmetry, the book starts and end with long form, next is individual couplets, and in the center you have a mixed format that pulls from Egyption wisdom.