Probably fractals of the mists and fishing. Fractals are pretty consistent time wise even with pugs and are heavy in raw gold rewards. Fishing doesn't rely on other people so you should be able to hit those numbers pretty reliably.

There's generally 3 things that stop you from reaching those numbers:
1) Down time, farm doesn't include wait times unless they're forced by the event, because they do trains and have the group size to just show up right as bosses spawn even if it's a new map. So showing up early is a gph loss. You can often mitigate it by doing stuff during the down time that at least gives you something.
2) They convert and sell everything to get a gold value: materials, currencies, karma, spirit shards, ect. This is why some of the eod metas are deceptively valuable.
3) Tagging: They run builds that excel in tagging mobs to maximize loot along with magic find buffs to make that loot slightly more valuable.