Just personally where I started.

Twilight highlands, potion of treasure finding if you can make them / find them affordable.

Just spamming elementals, mainly hunting volatile water and fire, gives you cloth, some decent vendor gold, greens to vendor or disenchant depending on your AH and maybe if you're lucky a sellable blue or epic. (You have to want it, man. These kinds of farms are incredibly tedious. Throw on a TV show or podcast and get blasting)

Check your AH for volatile water, fire, and life, see if the prices are attractive to you. I started doing this farm about two years ago when I had like 15k in my bags, got me enough starting capital to begin making moves on the AH and recently pushed up to 20 million. Volatiles are something I keep a pretty close eye on as I use them to make vial of the sands mounts and buy them up quite frequently.

Im sure theres plenty more suggestions but this is always my go to easy money maker if you just wanna smash some mobs and get some gold.

https://gyazo.com/0e099b0eb2c88119ef067080fb6afb7d

Blue circle volatile water, red circle volatile fire. Can be a really great farm in a group.