Dryads are fantastic, their sleep always hits against units level 1-3 not immune to mind spells. That won't help against cannoneers but will keep those pesky dwarves and miners under control. That aside the AI loves targeting summoned units esp poor thorns so pop out a stack to draw archer fire. Of course with Anga's ring they truly become a menace with their no retaliation.
By abusing the phantom sleep combo of cheese you can keep those massive dryad/lake faerie/dragonfly stacks in la la land while you clean up.
In Haas's dungeon I just snoozed my way through 10000 peasants!
Demonis is worth it for some good spell/arties and top units as long as that champion is guarding the portal
The lead up fights (there's usually two on the bridge) can be pretty tough...