@MoonOkami
For pure money grinding, the 4th areas (except
Darkspine, more on that later) have 3 pack mobs and the boss encounters,
which can drop high value trinkets frequently. Those trinkets mostly
have no uses, making them excellent sell to vendor fodder. The bosses
also drop 380 pebbles for every kill, which seems small but over time
that adds up. If you grind for extended amounts of time, you'll rack up a lot of the plushies, ambers, etc which sell for a lot to the vendor.
In terms of pure money potential, grinding in
Goldsea is most efficient, with Icerun close behind. Murkwood is decent
but less than the other two, however it does drop seeds for farming
which is a great way to stock up.
You do need specialized
teams to take down the bosses consistently though. It is no longer
possible to beat them with a single wolf + companion duo, so you'll need
specific team layouts that are good at beating them:
(Wolf breed + Wolf breed and Companion + Companion)
Murkwood, Icerun: Kit + Kit OR Jocol and Lunaria + Canictonis
Goldsea: Kit + Kit and Furmus + Furmus
Darkspine: Don't bother*
There is also options using the Krane if you have it, however as it is a Kickstarter companion it is unattainable for most.
*Darkspine's
boss has two problems. One: the boss is bugged and does not drop
pebbles like the others. Two: the poison output from the boss makes it
nearly impossible to counter with a traditional 2 wolf 2 companion set
up, making the effort and food needed not worth it.