Have you considered ```EntityEffectChangeEvent```?  I personally think Bukkit's naming of ```PotionEffect``` is misleading, especially in light of how they can be applied from other events that don't include potions.  Even nms refers to them as ```MobEffect```s.

I know it'd be a bit of a inconsistency in naming from a Bukkit perspective, but I'd almost like to see ```PotionEffect``` be the inconsistent name over time and everything else migrate to just ```Effect```.  This is a personal preference, I can't guarantee the core team would agree at this point.