Its not exactly a set editor, but, well, whatever floats your boat
As for how the deck plays, it's focused on a go-wide strategy with bodyguard characters mixed in to protect your Amber horde
For just two mana it can give any creature lifelink until end of turn, and then when you gain life in any way, you distribute a +1/+1 counter on a creature or enchantment you control
Once you get these artifacts on the battlefield, they start to boost all your next moves, from creating huge tokens and doubling power to ramping and giving counters
It is the increase of creature power and tempo in the cube combined with a decline in combo that has made Witness fall a little out of favour Survival of the Fittest is not as widely playable as most of the other cards in this list but will still fit in a lot of decks as cube decks are full of one offs and green decks are pretty high on creatures