Just to mention about Empyrean Merits or EMs. There are diminishing returns for them and after veteran level 99 they are not received any more. You get them every three levels between V3 and V99, the amount starts at 20, then becomes 15, then 10, then 5. I tried to add them up in 2020 and came up with 365 but the HC WIki says there are 410 total. EMs can be converted to Reward Merits (1x EM => 10x RM).
Approx six sets of purple or winter enhancements or divide out to lower RM cost recipes.
While EMs might (have been) a product of farming, I do not think realistically that farmers "farm" for EMs.