Vanilla group farming spots

[Apatheist]

Trash farming raids for BoE's and Hakkari Bijou in is doable with a decent tank or if you box more than 5. Especially with hunters or mages. Hunters can FD or trap pull so you only have to kill one mob at a time, frost mages can allow your tank to kite. A single decent BoE drop can sell for several hundred gold up to a thousand depending on the item. There's a fire damage ring from Naxx trash that is BiS for mages. There's also a nice caster staff from ZG trash.

Other than that, just farming dungeons is your best bet. Tribute runs for crafting mats and rare books will earn you around 150/hour. You can also charge people for fast tribute runs once you get efficient at it. Some people will pay 20g+ for a fast run and not to have to roll against other players for their preraid BIS. Farming BRD for dark iron ore, mats, BoE's, etc.

Where you farm depends on what the market for stuff is like on your server.

I have to say though, even as a boxer "farming" is still far less profitable than simply using the auction house well.