2-player builds for getting through dungeons. FYI, the first 2 builds are the player ones, the rest are heroes.
Catacombs of Kathandrax
High amounts of elemental damage, fire in paticular, so stock up on anti-nuke skills (WaH) and Rangers for defense. Daze from Thnderclap is good against casters as well.
Lots of Charr, which means lots of Fire damage. However, the biggest thing is to stock up on Ebon Vanguard skills, paticularly EBSoH and EBSoC. Due to some tight corriders, a Barrage/Pet theme might work. Also, Barrager's mean the entire group can stay inside Wards, all of them gaining the bonuses.
Cathedral of Flames
It's a rather mixed dungeon, but in the end it's quite easy. Some undead means Holy damage is quite effective, but overall you just want big, straight up damage for the charr.
This is really a very easy dungeon, so practically any decent team can do it.
There's lots of Hexes, so bring lots of Hex removal. Otherwise, just bring some defense for the Jotun; they can hit pretty hard.
Like Ooze Pits, this is very easy. Just don't bring a Minion Master.
There's lots of Conditions, Hexes, and corpses. So take advantage of that with the correct spells.
This is another easy one. Just watch out for Daze on the Incubus and some Daze/interruption or Condition removal for Wizards.
Shards of Orr
A very hard dungeon. What the undead lack from their vulnerability to Holy damage they make up for in defense. Some mobs containing up to 5 Skeletal Wizards, all of which carry Blinding Surge and Eruption, makes it a hassle. A simple counter is to use lots of Condition resistant builds.
Yet another easy one. Any decently balanced team can roll through it.
The good amounts foes means AoE and Minion Masters are good. Ranged damage is prominent, so a strong, high damage frontline with "Shield's Up!" syncing is prime.