I would add that fire elementals gain health if you hit them with lit torches, so you should absolutely not fight them with lit torches.
Also, imps and living rocks seem to be immune to fire (lit torches).
Zombies, on the other hand, are vulnerable to fire. I can get 14 damage against a zombie when wielding a lit torch and significantly less when wielding one unlit or using a hammer.
Red-eyed/aberrant pirates are best fought with composite bows and some distance away or golden swords, if you can find them. If you do have a golden sword, I would recommend reinforcing it with glue as often as you can so it will last for some time.
Slimes/gels are vulnerable to piercing, which includes swords as well as the pole weaponry and arrows.
Living rocks are good for target practice (with arrows and throwing), and need not ever be the death of an adventurer.