Probably either Bio (vegan) or Artemesia (not-so-strict-vegetarian). Or green bamboo. But the reason you found lots of vegeterian restaurants is not surprising

Probably either Bio (vegan) or Artemesia (not-so-strict-vegetarian). Or green bamboo. But the reason you found lots of vegeterian restaurants is not surprising: you were a tourist in a touristy area, and it's mainly tourists that look for vegetarian restaurants in Argentina! Source: I'm Argentine, and I live here. Also, I eat at those restaurants.