There are many, many fields in bee swarm simulator. The thing is, there are also many differnt color fields in the game. These colors are red, blue, and white feilds. Depending on your late game hive color, you might want to choose what field to grind at. To know what fields are where, here are the zones, fields, and their colors.
All images are made by Onett in the Bee Swarm Wiki
There is no 30 bee fields, since all there is, is 2 npcs that you will meet once you get 30 bees. Some more things you should know is that in the red and blue HQ, as well as in mountain top field, there is a field booster that will give a pollen boost on a random field, depending on which booster you use. The red booster boosts red fields, the blue booster boosts blue fields,a and the mountain top booster boosts white or mixed fields. The thing is, coconut and pepper patch cannot be boosted by these boosters.