Ravaging. one of the few sets that rewards you with more dmg for actually having to go on the full offensive. Too many other dmg sets reward you for taking dmg or doing very little to meet their conditions to proc.
Briar was also one of my favorite sets before the fix making its healing comply with battle spirit which also ruined its combat effectiveness (instead of the healing value it now has, apply minor health steal to all enemies you crit on while it is proceed).
7th+ Fury+ Veiled can or do all proc from you just maining buffs/debuffs and healing.
Maw of the Infernal...if that counts. Dirst time i saw itbin action was at a dolmen and I kept trying to kill it. Couldn't target it so I figured i was lagging. Saw it again in a dungeon....FG1 i believe. Kept trying to attack it...until someone noticed me and told me about it. Ended up usingbitbon my pet sorc and still love it to this day.
Blood moon on my Werewolf. I get all excited when it procs and I unload onto what ever I'm hacking at.