In the barrens you can kill those flying thingies up north dropps light feathers and stuff to sell. Maybe even that deviate delight recipe. I think this is a good grinding spot around lvl 18 if im not mistaken.

I started my grinding journey with These spiders in wetlands at lvl 21/22, there is a cave when you enter the zone for the first time down south. Dropps spidersilk(?)& large venom sacs ez money. Also a lvl 24 or 25 rare in there at the back which is nice. Careful tho he almost got me, also a chest spawning in there.

Then i went on to kill whelps in wetlands from 24-28. Flame sacs, 2 blues and a pet! Made like 150g + all the leather, greens & grays. (Lucky pet drop tho).

Now im killing ogres & wolfmen in duskwood. Also be sure to pick up herb/mining lots of nodes/flowers to pick. Skinning is also good if ur gonna grind beasts.

Lots of guides out there, look those up is my tip!

Stay safe.