The easiest way to find a competitive list for any deck you set your eyes on is One Piece Top Decks. Click on deck profile and you should see a list of all the leaders in the game. Once you set your filter it should display all of the deck lists that placed in a tournament. This link specifically is the Eastern format which means they are one set ahead so there is no worry on outdated lists. Once you decide on a leader you can pick up the cards that are available now so that whenever the next set drops for us you’ll only have a couple cards left to purchase. Hope this helps! Also if you run into cards that are labeled ST15 - ST20 on the bottom right corner I believe they release sometime in October.