Some of these feel undercosted, but the only ones that look broken to me are the earth one and the aether one. I'm at work so I don't have exact decklists, but I'll try to describe how I'd break those two:
Earth: For one, you could burrow your opponent's creatures to halve their attack. That would be quite devastating in and of itself, particularly in combination with diamond shield. (though if they also get 0: unburrow, then this point is moot) It would also allow you to play creatures in element and then immediately burrow them to keep them safe, a trick that currently only aether (with aether nymph or quint, and with very few targets to use it on) or time (with shard of readiness + anubis) can do.
I think that the earth one would also be extremely strong with shard of patience. You could play steel golems or damselflies or something and immediately burrow it, and then otk a few turns later, particularly given the unburrow/SoP synergy. You can in theory do this already with antlion/shriekers, but there's a turn of vulnerability without an additional card in the combo like quintessence or cloak.
Aether: This one only really strikes me as OP in multiples with flying weapon and possibly parallel universe. You could ramp spells up to rather insane damage fairly quickly. Depending on the interaction with bolts (+2 total on the spell or +2 on each 10 quanta) and psions, it could also get a little crazy. Psiontal with a couple of these and some AWs could be really scary, assuming it works that way.