OK the
panharmonicon works but since your creatures are "when" triggers
panharmonicon will activate there ability only a second time no more after that I would recommend
strionic resonator to keep activating your abilities anytime you like.
Panharmonicon works best for whenever another creature enters the battlefield or artifact. Whenever is the best trigger ability to use with
panharmonicon since it says when a creature or artifact
entering the battlefield causes a triggered ability of a permanent you control it actives that ability an additional time.
1.
ALTAR OF THE BROOD works well With
panharmonicon lands don't and enchanments don't count.
2.
GOLDNIGHT COMMANDER another good example.
3.
WARSTORM SURGE also works well.
You néed to search for whenever another creature enters the battlefield or artifacts if you wanna get the maximum out off your
panharmonicon.