I have been playing this game for this long and still have no idea what this thing is

[fadetree]

It's an interesting question. I tried to do some google research on the design and meaning of the class icons, but didn't find much. You'd think that there would be some historical design notes, but knowing how dev shops usually work there may not be. Finding out who were the graphics designers for original EQ by name would help, but I'm not sure how to do that. The guess that the necro one is basically a heretic's fork is a really good guess, I think.

I would guess that the chanter icon is based on the idea of an 'evil eye'. Why it's embedded on a leather covered paddle thingy might be to try and look like something tribal, but that's all I can come up with. There is a history of things called nazars that are protective against the evil eye, and they are usually circular or oval and have an eye embedded on them, the idea being that they can turn the 'evil eye' back on itself and thus protect the wearer. The action of the 'evil eye' attack would be to bring misfortune or to control the victim in some way, so this might reference either the enchanter's protective ability or also the ability to cast 'evil eye' type effects.

The 'third eye' that has mystical powers is a good guess too, but it's not clear that there are two otehr eyes involved and it doesn't look like much of a head or face. Both ideas may be in play here, or else the designer just thought it looked cool /shrug.