[andrewas]

available early on in the game :flametongue, valygars sword - poison works to, and a glitch means bleeding damage counts as poison - flail of ages, arrow of fire and acid, melfs acid arrow, fireball (use with care) ,flame arrow, a spider statue from somewhere if you want to poison, sumon spiders, again poison in melee, but at somepoint you get sword spiders which are useless for this, assasins poison, cloudkill (i think it works). i recall that someitmes you can chunk them and that works, but i dont know if thats BG or not. the druid spell flame sword.

thats some of the more obvious way. much later on , with ToB installed, you can get such powerful artifacts as a club of detonation, andurval the burning sword, and numerous others.
both of the ones i mentioned can be found in a certain keep, if you want to die quickly.