Most of the old traders no longer sell stuff and cannot be interacted with. Now you can only purchase gear from Reputation vendors or from the Auction House, though some traders do re-sell stuff.
Traders that you should be able to trade with in Novo, by right-clicking them or pressing Z, include:
The Food+Drink Vendor in trade district, all Craft Trainers, all Mirra Vendors (Servants of Light), Reputation vendors (with the blue+white rosette above their head), the Referral vendor in the bank, the Rune Vendor (Gibberling district) and the Guild Master. Check in resale and you might find some bits of gear, particularly around the Craft Trainers and bank. The best source of gear is the Reputation vendors for the appropriate level, who sell Rare (blue) gear, but they require time to get reputation up to 25k and can be quite expensive. If you have a profession you can also try to craft some for yourself.
I hope this helps a bit