lvl 40 Maongs
Lvl 41 Maongs, Bunwangs,Ultra's - there all in the same area at ferry.
You can chop and change depending on the Bot population. Handy if you have a wolf same level.
For added fun try Spiders, but without your wolf.
Be careful of grinding though you'll get banned in this area on Tibet for Botting.
It really depends on what you are comfortable with and how many pots you want to expend, your build and also your level gap.