Have you found any mobs that are useful for mind controlling, as in they deal more damage than you or have useful buffs/debuffs? There was a thread like this in the official forums at some point, haven't seen one here though.
I've found the following mobs useful!
- Twilight Emissaries in BRD have a spell dmg buff that lasts for 30 minutes
- Twilight Fire Guards in Searing Gorge. You can MC them and buff yourself with unlimited (Afaik) stacks of fire shield, each dealing 50-140 damage per 3 sec. to all nearby enemies, lasts 10 min! There are other mobs in the game too that have the fire shield buff, like Kobolds in AV.
- Bloodwarder Menders in Botanica have a 30 min buff that boosts spellpower by 300, useful for buffing all casters in the group
- Dark Rune Shapers in Halls of Stone have a buff that increases int by 200 and hit rating by 50 for 2 minutes :/