Would any of these work well?

[Vexenu]

Basically, if you want a true power duo, it must involve an Enchanter. The class takes skill and constant attention to play effectively, however (you will always be charming a pet, dealing with potentially dangerous charm breaks and re-charming), so if you aren't up for that then don't bother. Enchanter pairs well with Cleric, Shaman and Druid, each combo with various strengths and weaknesses. You can also pair with another Enchanter or a Necro, but those pairings require both players to be highly skilled and attentive, and are more dangerous if things go wrong.

If you want a powerful but lazy duo, then it's all about the Mage/Cleric. Especially with a High Elf Cleric who can more reliably land Lulls with their high CHA. Cleric has good CC with roots, stuns and lulls, and obviously brings the heals as well. Mage brings the DPS and the tank. This is a solid duo both outdoors and in dungeons. The only knock is that it might get boring for both players, since they will basically be doing the same thing over and over (/pet attack & nuke, or heal pet & root/lull mobs). But really, that's just EQ. You're either doing one thing over and over, or a few things over and over.

Mage/Necro is more of an outdoors leveling duo than a powerful duo, although a skilled Necro and Mage could probably do some dungeons. Definitely more dangerous than any other combo listed for dungeons, though, since it lacks both the true CC of an an Enchanter and the heals of a Cleric, which every other duo has at least in part. Mage/Necro would have to make due with the 2nd rate Necro CC and third rate Necro heals.