If you control two copies of Echoes of Eternity and you cast a colorless spell, each of their second abilities will trigger
And this distinction often matters more than you'd think
These are spells with no determined casting cost, meaning you can assign whatever number you want to it, provided you have the mana to spare
Theyre still playable, but Id much rather give a card as a bargaining tool to another player in order to ensure the board is fully wiped, before getting my best creature back again
Like Dragoon Spear, its an okay rate up front
If a mid-range approach isn't your speed, you can always take a more control approach with Kenrith, stocking up on counter spells and some hatebears effects to control the board