I don't know if there's a complete source available for all such information. As a general rule of thumb, I use:
-Acid works on everything except for a few rare exceptions (monsters that spit acid, plus ants)
-Lightning works on just about everything except for a few rare exceptions.
-Ice works many creatures, but a fair number of things are resistant.
-About half of all monsters are immune to fire, notably all daemon (&) types.
-Magic missile works on everything.
True vulernabilities are rare and usually pretty obvious: cold creatures are weak against fire, fire creatures are weak against cold, some other creatures (liches) are weak against fire.
Note also that some monsters "shrug off" bolts. This is not the same as immunity--they will shrug off bolts of all types equally well. This just means you need high willpower/mana/spell effectiveness to make the spell stick. Repeated applications are necessary for particularly dextrous monsters. Ball and touch type spells (fireball, acid ball, burning hands, petrification) can never be shrugged.
Last edited by JellySlayer; 02-03-2010 at 09:32 PM.
Hoping to win with every class, doomed. Archer, Barbarian, Bard, Beastfighter, Druid, Elementalist, Farmer, Fighter, Monk, and ULE Priest down.