I regularly do A Sheep in Antlion's Clothing, the ENM which has a 10.7% chance of dropping hagun (~2,800,000 G on our server) with Omecle and a friend from our linkshell. We've been doing it every Friday for a month now, and it's been going fairly well. Three forager's mantles, a cloud evoker, and one hagun in four runs is hard to beat.

I also do ISNM 3,000 Shadows of the Mind with some regularity as well. In five runs, I've gotten two khroma ores from it, and even when it doesn't go well, you'll usually walk away with equal or more what you could make from the IS if you'd spent it selling imperial gold pieces.

I irregularly do the same thing as Del Murder--purchasing scrolls and selling them for a small profit on the Auction House. I've had so much other stuff in my AH lately that I haven't been able to do this quite as well.

I also gil garden with my main character and three mules. I purchase wildgrass seeds in Aht Urhgan Whitegate at 360G each. Combine those with a lightning crystal and the yields are water crystals, azouph greens, and sharug greens. Each pot can yield 8-20 of the greens which can be sold at full fame for 255 G each at your friendly local NPC. I pull in anywhere from 100,000 - 130,000 G every six days doing this.

Also, although I haven't done it in a while, I usually throw myself at some BCNMs as well, although I don't tend to have as much luck with those as I have had with ENMs and ISNMs.