While only scarce amounts of fragmented writings in Etruscan and other languages spoken on the italian peninsula have survived (other than Latin of course), the Greeks had a strong literary tradition and a more significant corpus of it has come down to us in the present. The Greeks also founded colonies in Sicily and southern Italy as a part of their Mediterranean trading networks, so surely they must have been in contact with the locals in the rest of the italian peninsula (as evidenced by the Etruscans getting their alphabet from the Greeks). Thus I'm wondering if anything was written down that has survived describing the places and peoples there. My curiosity isn't just limited to the Latins, but to any groups there.
Yes. Discussions of Italy start as early as Herodotus. "Italy" isn't always the same though; it's a term that developed over time to mean the peninsula between the Alps and the Ionian Sea. But Greeks were talking about it from the 5th century.
Here are some notes from my own poking around this issue, in reference to Herodotus:
All locations of references to “Italy” in Herodotus are 1.24, 1.145, 3.136-8, 4.15, 5.43, 6.127, and 8.62.
Places: the river Crathis, Croton, Metapontum, Sybaris, and Siris
Herodotus does discuss other regions of the peninsula that in the 20th century is called Italy, but not in association with that name.
Etruscans and Umbrians he doesn't consider Italian
Antiochus, preserved in Dionysius of Halicarnassus, roughly a contemporary of Herodotus, had a slightly more inclusive definition of Italy, but it doesn't get you much more.
There is also the Periplous of Pseudo-Skylax, but that doesn't use the word Italy. It is a port-by-port account of what you find in the Mediterranean, which includes what you call Italy now.
After that, we seem to be getting into sources after the 2nd Punic War.
An inventory of archaic and classical poleis [EDIT: That's the right title] probably has the best bibliography of what is known about Italy at different points, if you can get your hands on it.
Once Roman historiography gets going in the 3rd century things start changing fast. As far as I'm aware, those are major pre-Roman sources.