Ya know. It's not the best source of gold, but it's all new gold: Run old raids and vendor all of the gear. In about an hour you can do Highmaul on LFR, Normal, Heroic, and Mythic and get about 6000g total. Some of the other raids aren't quite as fast, but generate similar amounts of gold. You can get some fun new (old?) transmog too if you haven't done much of it.
The expansion brings a major change to the PvP ruleset on each realm. Every realm by default only allows players to attack NPCs in the open world; players who wish to engage in world PvP now have a setting called "War Mode" that can only be toggled on or off in their faction's capital city (i.e. Stormwind for the Alliance and Orgrimmar for the Horde). While in War Mode, players have access to new talents and abilities, as well as a slightly accelerated rate of XP gain. Characters with War Mode activated are only able to see other players with War Mode, unless in their own capital cities.
M Madmortem Alliance Madmortem Horde Magtheridon Alliance Magtheridon Horde Mal'Ganis Alliance Mal'Ganis Horde Malfurion Alliance Malfurion Horde Malorne Alliance Malorne Horde Malygos Alliance Malygos Horde Mannoroth Alliance Mannoroth Horde Marécage de Zangar Alliance Marécage de Zangar Horde Mazrigos Alliance Mazrigos Horde Medivh Alliance Medivh Horde Minahonda Alliance Minahonda Horde Moonglade Alliance Moonglade Horde Mug'thol Alliance Mug'thol Horde
Disagree with your comments on Sky Golem. You need about 4200 ghost iron ore make this. Ghost Iron ore turns into bars which are used for Jard's Power source, but you only need 300 bars for that. You also need living steel which is transmuted from triullium, which in turn is transmuted from ghost iron. If you have an transmute master you proc on average about 20 additional trillium bars, that's like 7000g in savings.
I think that's server dependant. I make a lot of Golems, but the price on my server is high enough that you could buy all the living steel and still make about 20K (almost 200kg on AH). Its just that you proc all the way up the chain. You proc 20% of your trillium, and then 20% of your living steel. SoH and Ghost Iron are such low effort farms, too. 20% of 180 Trillium Bars at 500g is 18k more profit, 20% of 150 Living Steel at 3500g is another 105kg. That's an extra 25k profit per Golem. If they stop selling stockpile them for the next expansion, they always boom with the price of herbs. And a consistent 20% proc rate is the opposite of RNG, its extra free stuff as a benefit to completing an extra quest (not to mention for new alchemists the investment of leveling Vanilla Alchemy). You're looking for some get rich quick scheme, where the real way to build wealth is patience and volume. No market is going to be viable because you want it to be. Only because you make it viable.