If you were looking for one anachronism to make the fortune of a large grain producing region in antiquity, it'd be distillation...
On a side note, I'm genuinely interested what the traditional drinks of the Peuketii are like, and whether they have any regional specialties.
do any of our barbarian Subjects have any sheep? if so the we can get wool and start a clothes industry
Our barbarian subjects have tons of sheep, and I believe there is still a yearly ritual where the Pueketii (or possibly Egnatia?) bring us a flock of sheep and we all get drunk and have kebabs.
@Ironanvil1 would be able to say more.
One thing to keep in mind here though is that pretty much everyone makes their own clothing in this period, or will have clothing made by their servants/female family members, or may possibly see a professional clothing maker if they're exceptionally wealthy and want the finest and most ostentatious clothes - I don't know if this is a thing in Eretria. There isn't an economic advantage in shipping clothes right now; Too much bulk for high shipping costs, for a product that is either literally personally tailiored for the elites, making shipping pre-made clothes pointless, or far too expensive for the overwhelming number of people to want to buy considering they can make their own.
Another more general point to keep in mind with all these kind of "what if we did X" ideas is that our people aren't just sitting around waiting for something to do right now. There is a lot of labour that goes into running a primarily agricultural society of tenant farms, and all the basic supporting industries. So any new thing we do, to a certain extent, has to be traded off against the other things our people are doing, which means it needs to boost net productivity or be very valuable. We have a bigger reserve labour pool than most, but it is far from infinite.
So mostly, we're talking about small, iterative improvements on what we're already doing, that boost productivity in some way, rather than kick-starting new "industries". The exception is stuff like salt, which is so hilariously valuable that it's worthwhile.
We need to settle the affairs of the Messapii next turn, but I'm sure the update will focus heavily on that. One thing though I had a thought of was establishing a Sacred Grove dedicated to Artemis outside Ereitrea's walls, nearby the festival of tribute, with an altar and maybe other attendant structures as appropriate. The Peuketti and Messapii, plus even friendly Dauni, could be allowed and invited to make sacrifices there to establish a cult-center for Artemis and their own ancestor Orion.
Not sure mind if entirely in character to allow barbaroi to sacrifice in such a grove though it's still a good way to honor Artemis even if "Hellenes only."
That would be really nice. We could even roll into the cattle-trading idea. If they're bring oxen to the city once a year it's a natural step...
Looking at it right now, the festival of Artemis in Athens was held on the 7th of the month of Thargelion, or around the ballpark of the 25th of May. If the timing of our Artemisal festival is similar, and she's a goddess of the hunt so you'd expect spring/summer, then that perfectly lines up with when the yearly cattle drive would be.
Bring your cattle outside the walls, do some trading, make sacrifice with your best bull (or second-best, if you're not quite as pious) at the sacred grove of Artemis. It's a pretty good system.