If you want to keep using a pole, see how the bee hive works for you. It's a lot of groups of 3 monsters that die fast but hurt a bit.
If not, try:
-the area between giran and giran castle.
-death pass
-plains of the lizardmen south side
-cruma swamp (not the dungeon tho)
-execution ground
-the catacomb around execution ground
-the necropolis around the partisan hideaway
-field of silence (like the other guy said)
-field of whispers (ditto)
Prolly a bunch more places but that's all I could think of.