I have generally found, the following to be pretty good at killing most mobs.

LG Conjurer (lots of options here but don't kill good stuff)

Shield Pallies (same as above)

Defense and Utility shifters (some forms are bad so risky but, most def forms take forever to kill anything but they can get the job done Did a lot of exploring with a Dillo/Fox/Sand Lizard once, dillo was great for rooms where you get paralyzed, fox could kill most stuff and sand lizard to heal if neccisary)

Bards

Hunter Rangers (although you have wilderness restrictions)



Basic Rule if it can tank and has some self heal it can kill mobs pretty well, if it can't tank you will have problems..