Zero WP.

What would be a good place to farm WP.

Mirror World Spam? (Which is giving me an obnoxious amount of fragments and coins)
or some mystery spammable boss that i don't know about.

I don't know of any spammable bosses, but doing hilla, easy ark, 3 kritias mirror world dungeons daily (this is a really good one right here), and root abyss are decent. Also, grosso polpo and the sea serpent at commerci give WP in decent chunks. Other than that, just farming mirror world dungeons is the best option.

Yes + Kritias.
Easy (3 times a day) - You get like 55-60 for finishing the dungeon.
Hard (3 times a day) - You get like 80 for finishing the dungeon + the monsters (every monster) give 5 WP each (as much as I remember).

Mirror world in general seems the fastest i guess then, thank you.

At least it gives a whole bunch of useful things.

Very much seconding hard mode Kritias, I get more than a full reset per run.

I believe the modes in Kiritas give 5 WP per kill instead of 1 like mirror world. They are decent exp too. But as Justin said, kill any easy boss you can too, they give about 80 WP. Then its back to mirror world runs.