My suggestion involves chaos clerics in the labyrinth. A fun, yet touchy subject for me personally. Several strategies for using them exist, from the most basic (des, soul shatter, flee) to somethings I've found out the hard way in certain gates. For example, a stationary mob to a CC is a resource. A tricksome resource that might just kill you, but a resource none the less.

After curse/despair/desecrate the usual haul for a drain can be in excess of 40 mana, combine that with a good dodge, as elf or maxed out monk dodge and things can then go from the boring wait to see when you'll finally regen to take on mobname, to locking it in a room with hellfire, don't forget to blind and still it too, and using it to recharge your health, mana and moves by way of draining it. Just a little strategy I was informed of recently.