You now have three colourless mana floating, and can do it again: tap Basalt Monolith to make three more colourless mana, pay three to untap it, copy the ability using two colourless and Rings of Brighthearth, untap Basalt Monolith once, tap it to make three more colourless, and then untap it with the copied ability
(It enters with a +1/+1 counter on it for each color of mana spent to cast it.) At the beginning of your end step, if there are thirty or more counters among artifacts and creatures you control, this artifact deals 10 damage to each opponent
Thats a lot going on for this deck, but this slots in nicely with Edward Kenway
His synergy with fetchlands and legendary lands alone is worth noting, but hes got plenty of other tricks to play with Stoneforge Mystic and such
Peregrine Drake Peregrine Drake is basically only used as a combo piece in blue and Simic decks, but it fulfills that role quite well