There were 4 monsters released. Radobahn, Banbaro, Barioth, and Zinogre. The first three can be found on the map in game after their respective quest. Zinogre will be exclusively found in the Hunt a thon coming December 15th.
I know Banbaro was the 10th quest set. I lost track after that, but I think Barioth was about the 15th quest set and Zinogre 18 ish. Reddit may offer a more detailed answer.