1st of all Pkin
This one I recommend for most players as it is very easy to do and the loot can be great.
Mainly Pk blue names and black names, if you do this you will get the whole of their inventory from them.
BUT BEWARE: OTHER PLAYERS CAN PICK UP THE LOOT SO EITHER DO IT WHERE NO ONE IS AROUND OR JUST GRAB THE BEST BITS QUICKLY!
2nd off EXP balls
Now this i would only recommend for higher lvled players but when you are a high lvl you will get easy fillings up.
I recommend the high star ice creatures as from 3 of those, you get 1% full.
Right now heres a bit of a lower lvl method.
Pick up all you can find then if it is refined change to an eudemon crystal if it Unique/Elite/Super/ Or has any sockets or has + numbers then create a stall and sell it. Ask a close friend for a price. All the normal stuff sell to an NPC.
I hope this Helps everyone i will be posting even more stuff soon, so until then, Cya!
=)