We can do some pretty nifty stuff here, sooooooo, here's mine and Mina Holly's suggestions :D
mage -> red gem-yah this is cool, or drops sp item like grape (or grape juice)
wizard -> panaceas (Mina says status really hurts her wiz bad) or red gems still
high wizard -> Red Stones or +int food
sage -> yellow gem-YES PLEASE <3
professor -> cobweb-YES PLEASE EVEN MORE <3<3<3 *I HATE TO FARM THESE!!!!!*
acolyte -> blue gem-seems good to me :D
priest -> Blue gems again or holy waters
high priest -> Uhhh...we couldn't think of a good one ._.
monk -> ......o.o?
champion -> +int or +str food
thief -> zeny-could be fun :3
assassin -> red gem?
assassin cross -> poison bottle-OMG make this extremely low, or make it drop the ingridients to this stuff.
rogue -> Zeny or Ele arrows
stalker -> Quivers :D-no immaterial quivers though
swordy -> Orange Pot or Red Pots
knight -> White Pots
lord knight -> Small Drop on Ygg Seeds? o.o
crusader -> Grape Juice or Strawberries
paladin -> ....o.o?
merchant -> zeny too-probably best or
blacksmith -> rough ores?
whitesmith -> pure ores-seems good, Mina says oris better but I dunno
alchemist -> Fabrics=harder to farm than stems :3
creator -> alcohol-yah this'll be cool
archer -> arrows?
hunter -> traps or +agi food
sniper -> Quivers-do not give immaterials as possible drop
bard & dancer -> ...>_> dunno
clown & gypsy -> ...Dunno again
taekwon -> ?
soul linker -> ?
star gladiator -> ?
ninja -> kunais-yah I like this
gunner -> bullets-yah or SP healing items, they have sp eating moves D: