I think Endless One could be fine in a deck that has a focus on the +1/+1 counters on your creatures with cards like Avatar of the Resolute, but as a big payoff spell, the other options are miles better
The addition of so many new Dragons to the game gives this deck a big boost in power, with some powerful new additions increasing the decks power above the rest
Phyrexia: All Will Be One Phyrexia: All Will Be One introduced a tweaked version of the living weapon mechanic from Mirrodin Besieged
The rest of OTJ's Green uncommons At first glance, Betrayal at the Vault looks like a powerful effect that would give you a two-for-one and maybe that is true because it is an instant
Id generally stay away, though its technically playable if you need it to be
High Utility, Low Price Apprentice Necromancer Archaeomancer Azami, Lady of Scrolls Go for the Throat Rakdos Charm Reality Shift Terminate Chaos Warp Crosiss Charm Curse of Verbosity Decree of Pain Clone Legion Fellwar Stone Darksteel Ingot Worn Powerstone Nevinyrrals Disk Curse of Opulence Look, I know three-mana-value rocks are out of favor (unless theyre Cursed Mirror, etc.), but if Darksteel Ingot has no place in the format, then I want no part of it