Dolac (Zagreb) above the main square at the foot of Old Town is not just a place to buy fruit and veggies. It is a crossroads where people come to see and be seen; to trade gossip; to relax with a cup of coffee; and to meet friends. Early morning is the best time to visit because that's when the bread is freshest, the displays the prettiest, and the people the most interesting.
Pazarin (Split) is reminiscent of a Turkish bazaar in looks, sounds, and smells; booths and tables line both sides of Hrvojeva Street outside the east wall of Diocletian's Palace from the Riva to the Silver Gate. You'll find the usual assortment of produce here. You'll also find a large variety of textiles and some of the most persuasive vendors anywhere.
Bjelovar's market is quite civilized and partially covered. It is noteworthy as the place to which farmers from Croatia's agricultural belt bring their best produce, dairy products, fish, and meat every day. The market is at its busiest from 7am to noon, but a few vendors stay around until 6pm or so to catch people on their way home from work. The later it gets, the lower the prices go.