More lately, I have begun to see people fighting the ants in the alignment maze, as well as people fighting within the Forest with the spiders. Sooner then later, these areas will become a bit crowded.
As it stands, infant spiders and army ants are the better sources of experience through battle, but there is a limited number of ants, and the spiders sting quite fiercely at times. Perhaps there can be another area that has similar experience gains to those of the army ants or the infant spiders on the grey section... or even the white section?
I have hunted pigeons, fleas, flys, crows, doves, mosquitos, squirrels, hummingbirds, and a few others little creatures.. and they give hardly any experience at all (roughly 2-3 after they flee).
Equally important IMO are nonviolent ways to gain comparable experience.
Violence has gotten a little over-emphasized at the moment largely because the Violence Skills were among the first to be implemented. We've been a bit old-fashioned that way: we kinda chose to prioritize some of the traditional MUD stuff over some of the more radical departures from tradition we have in mind. This balance will begin tilting the other way very shortly, and I think the differences will become increasingly visible.
BTW be careful attacking things outside the "hidden" areas such as the spider or vampire forests. Any cop that comes along will kill you fast. And remember that in NW all the citizens are all cops, in their way (although they don't necessarily use lethal violence). I think you might have been pretty lucky so far!