Agatha's Soul Cauldron Fittingly for a set about witches and fairy tales, our top spot goes to a witchs cauldron, specifically Agatha's Soul Cauldron
Additionally, mana dorks don't work if this card is out
There are also cards that let you gain mana rapidly even early in the game, or rifle through your deck to select a specific card, or still other special powers that compound the power of the awful beast youre chained to
Unlike Wellwisher this doesn't need any infrastructure to work, and it doesn't tap, so you can attack, block, grab equipment, and more
Having non-Wrath solutions to cards like Avenger of Zendikar or Entreat the Angels goes a long way in some matchups and will have you saving your Declaration because it is the only card you have than can help
Asses to ashes, Donkeys to dust