Where do I start? There are so many ways...a good example that comes to mind is that I needed to kit out my Shaman with Titansteel Guardians, so that's 4 at roughly 1000g each. When I had 1 to go I saw the end in sight and decided to put a burst of speed on to see if I could raise 1000g in an evening of WoW.
Dailies are always good sources of gold, so I got my team together and hit the ebon knights quests and some of the other ice crown dailies. Not all dailies are suitable for boxers especially collection quests so I always skip those.
Ebon Knight Quests
Now: and can be done at the same time. Don't use the gryphon to kill the mobs, just get your team over to one of the towers and land, start killing the gryphon riders, as you kill them use the pot you received for , there you go! Two quests for the price of one.
A personal favourite as my multibox team lead is a Paladin. From the questgiver fly NNW to the round arena area where all the mobs are sparring. Round them all up, burn them down, loot and deploy your flag. A nice thing here since patch 3.1 is you don't have to target the dead mob to plant the flag, it will just plant itself on the nearest available. Very quick.
This from a boxing point of view is hilarious. Now you could just get one of the team to kill the riders and they'd all get credit but HEY! you have 5 in your team and way more than 5 guns. What I do is put everyone on a gun and angle each one with a different point of view, then as the riders fly by I hit the 3 button and they all fire. This quest can be completed in a manner of seconds.
Another nice and easy. Fly your team to where you pick upp the dragon and position them so they're equidistant from the 4 closest buildings at about 60 feet in the air. Fly one member to the dragons and mount up, you can now do 2 circuits around your team which will get you 8 buildings on fire even though you only set 4 on fire as by the time you get back to the first one the cooldown is complete.
So that's the ebon blade's
Airship (I'm horde so it's airship)
Blood of the Chosen, with this one position yourself the top of facing the top of the path leading to the city, there's a guard there and if you attack him 4 more spawn, so! do that 4 times and quest complete.
So there's 4 multiboxer friendly quests on the airship making 9 in total, 8 of them pay 13g and Neutralizing the Plague pays 22g.
Total = 630g
Now add 50g in coin drops/selling greys taking the total to 680g. I haven't even bothered to include 5-8 green drops and at least 2 stacks of frostweave. This is one of the great parts of boxing - you keep everything.
Still 380g short so luckily for me the heroic daily was Grundrak 5x22g + 20g in coin + 15g in greys + 1 frozen orb which sells for 60g on my realm + maybe 5 greens + boss drops I couldn't use
Total from the heroic = 255g
Gold so far = 935g
A measly 65g short - well one of my alts is an enchanter so, DE'd all those greens and got 2 stacks of infinte dust = 120g.
Total=1055g leaving 55g for repairs.
So this is the joy of multiboxing - I needed gold so each quest I do I get gold x 5. Each instance I do I keep all the loot and I can go when I want.