one piece tcg: royal blood [op-10] booster box (OP-10) – The Awesome Card Shop This Booster Box contains 24 Booster Packs Bandai One Piece Royal Blood

This turns off spellslinger decks incredibly effectively so removal will likely be heading your way throughout the game

While not uncounterable, this guy is very difficult for U/B decks to deal with

Its two useful tools in one clean package

Black Market Connections does amazing work in this deck, like any deck, but you could play Maskwood Nexus if you care about tokens or Phyrexian Arena to keep up the card draw

Mitotic Manipulation (an underrated blue ramp piece in its own right) can find Islands and Swamps when you want extra mana, but it can also be a way to dig for another Nazgl to have the Ring tempt you and pump the team

Personally, I can't comfortably argue that Green is the most competitive mono-color in commander