(note, I don't actually have Antiquitas yet, gonna buy it next month on steam. Gonna gift it to my friend too. We both really enjoy My Colony however and love this style of game...now onto the suggestion)

I'm not sure how Carthage could work, but they (as far as I know) relied a lot on trade and naval based stuff. They also used quite a lot of mercenaries (again as far as I know). Which could be similar in a way to Draconians from My Colony, but mercenaries instead of slaves and be probably a bit different because of that. They could also be big into trading, though not entirely sure how that mechanic could play in. I know in My Colony there is trading, but not sure how it could be a focus.

Carthage and Rome were fierce enemies and could make for a really interesting civilization.