So, thinking (in the most loose interpretation of the word) about which foes classes have advantages or special tools against: Necros: undead Paladin: unead Mage: summoned Druid: summoned Ranger: humanoid What else? And who should have benefits against who?
Well, there are the obvious case, where mobs have a really high resist against a specific damage type. Some mobs in VP, seems to only be vulnerable to specific damage-types, I guess that can hit some classes hard. I seem to remember that in AD&D that golems were immune to all forms of magic attacks, thankfully EQ is not AD&D. As for your list, I can't think of anything to add. Do Druids/rangers have anything special for plants? Shaman:undead? I don't know a lot of classes... Personally, I think wizards should have an advantage against planar beings, we aren't called "Plane-shifters" for nothing...
sk, nec, cle and paladin all have anti-undead things sk & nec have anti-plant things cle & dru & mag have anti-"summoned"(construct) things rng have anti-people things dru & rng have anti-animal things wizards have one each anti-dragon & anti-giant thing, it was a special Velious faction deal