The Spirit Realm

I remember my first slow mitigating mob like it was yesterday. My poor chanter alt kept casting slow waiting for it to land fully. Eventually got summoned and squashed, LoL! After that I decided that mostly was enough.

Boleslav

There's a few mobs in todays game that are fully slowable. There's a DoN mission where you have to get bone chips, I believe the mobs that drop the chips are fully slowable.

Also, back when BoT was the spot for grinding, did mobs mitigate slow back then? I quit playing shortly before Omens came out, and I don't remember much about who mitigated what back then, but now it seems that a lot of old mobs don't mitigate slow.