Some Creatures you can play are already discard outlets, such as Angel of the Ruins and Archfiend of Ifnir
Its hard to ignore a repeatable mana source that can pretty easily make this much mana, though, so get on it
Its hard to argue with a spell that can put a +1/+1 counter on your best creature and phase it out to keep it perfectly safe from all manner or removal or sweepers
2024-06-07 Echoes of Eternity's first ability doesn't copy the triggered ability
I look at things like the watermark matters and outside of the game assistance cards as being fun includes in Cube, the one-off mechanics like blurry, triple strike or protection from black borders all work within the rules of the game provided that youre open to the idea of them, the squirrel theme feels completely black border if the game allowed for more whimsy (easily a topic for another article), and a good chunk of the legendary permanents seem very well suited for Commander
Just make sure both Energies are different