Works of Aristotle and Plato, Pythagoras, sure... all of that.

But if you ask me, obviously I'm going to give you alchemy :)

Zosimos of Panopolis, and Hermetic occult beliefs went from Egypt (where they were known in Roman times, because Zosimos lived in the 3rd century or so, so not ancient Egypt, but Ptolemaic Egypt).

That knowledge went via Jews and Nestorian Christians to the Arab world, and only slowly trickled back into Latin through folks like Ramon Llull (in Arabic Spain, but really Majorca), and even folks like Albertus Magnus and (probably Pseudo-)Thomas Aquinas to Cosimo de Medici in Florence who actively sent people out to bring back knowledge like this.

Through that the spirit of experimentation and classification was brought back--though in a very occultist form (tying Hermes Trismegistus to Moses of the Bible and Miriam the Jewess to Moses' sister, etc).

So some chemical equipment. Like the stills and the 'bain-marie' ...things that lead to control systems and new feats in engineering (used in such diverse applications as water fountains and controlling temperatures in furnaces, etc).

Astronomy and math made a huge comeback, but so did astrology and magic. All of that went hand-in-hand until the Early Modern Period (and still took a century to die out).

Okay... I'm jumping all over the place.

Agriculture is NOT an example. The (improved?) plow, etc were discovered/invented in the "dark ages" ...and overall the "renaissance" is a bit of an exaggeration.

Besides geometry and astronomy, in truth much more "neo-pythagoreanism" and neo-platonism made its way back into vogue... really just systems of magic, occult, and spirituality, and less science that you'd think.