With all those alts I suggest running the following raids
Mythic Highmaul
Heroic Highmaul
Normal Highmaul
Mythic Blackrock Foundry
Heroic Blackrock Foundry
Normal Blackrock Foundry
Mythic Hellfire Citideal
Heroic Hellfire Citideal
Normal Hellfire Citideal
25M Heroic Endless Springs
25M Heroic Mogushan Vaults
25M Heroic Throne of Thunder
25M Heroic Heart of Fear
I did this on 5 alts and averaged 150k per week plus pets and mat from the runs id throw on the AH for another 50k (200k gold a week on 5 toons) This is by far the easiest way to make gold plus doing it on different classes you'll unlock a lot of transmogs and multiple chances of mounts.
The downside to this method is time. on a fresh 120 casually clearing these raids could take about a day.
If you are going for loremaster I suggest leveling fresh with an allied race for the heritage armor. and just start clearing zones. If your main reason is gold, i suggest looking at other options
Farming raids on a bunch of alts, and then collecting mats to put on the AH is probably your best bet. Lucky I don't think the warframe mount is going away any time soon so you don't have to run ALL the raids i listed every week. I'd do just the WoD raids and maybe the shorter raids that drop mounts I dont have