![Image](http://images.wikia.com/dothack/images/9/95/The_World_Classes.jpg)
The first group on the top left is... I think possibly... the Blademasters group; the second on the top right is the Twin Blades group; the third on the bottom left is the Harvest Clerics group; and the fourth on the bottom right is Shadow Warlocks group. The last two on the center of the picture is possibly special classes as it does not connect to any of the others, but seeing the iconic symbols, its possibly looks like some type of alchemy and weapon-smith categories.
Though it is hard to foretell for sure, anyone has better reading and translating than I am? It is hard to read the names of it. Thanks.