I'm trying to find good forms for a druid who has taken
city shape, and am coming up a little blank. The druid's at level 11 at the moment, and at level 12 hellwasp swarms are available (which is really nice, considering their whole possession thing is gained by wildshape), but I'd like to find a few more forms that work nicely.
Obviously, this is almost entirely a city campaign. Something with flight that can carry around the party would be nice, but not necessarily needed. Houserules have netted the druid a winter wolf for an animal companion, so something that synergized with that (combined with character's wintery theme) would be especially nice.
There seems to be a lack of medium or smaller vermin between 4 and 53 hit dice in the SRD. Are there any other books I should check?