I did goblins till ~30s in melee and then switched to Moss Giants, it might still use a bit of food, but I think it's worth it. For mage, stick with non-combat methods, get your mage high enough from quests to do teleports till superheating, then superheat till high level alchemy. Ranged, catablepons are a pretty good at 30+, they barely hit and give a decent amount of xp.