A long time ago I made a comment like this, and honestly, with how the game has evolved in the One Piece Card Game, it doesn’t seem that crazy anymore.
Purple/Black Leader Franky
All of your {Water Seven} and {Franky Family} type cards in your hand have +1000 Counter.
[Your Turn] [Once per turn] When you play a Stage card, this Leader gains +1000 power during this turn for every 2 cost of that Stage. Then, at the end of this turn, you may trash 1 card from your hand to keep that power until the end of your opponent’s turn.
With cards like:
Rocketman
Purple Stage
Cost 2
{Water Seven}
[On Play] Look at the top 5 cards of your deck. Reveal up to 1 {Franky Family} type Character card with a cost of 5 or less and add it to your hand. Then, place the rest at the bottom of your deck in any order.
[Activate: Main] You may rest this Stage: DON!! -1, play up to 1 {Franky Family} type Character card with a cost of 3 or less from your hand rested.
Battle Frankies
Black Stage
Cost 4
{Water Seven}
[Activate: Main] You may rest 2 of your DON!! cards and trash this Stage: Up to 3 of your {Franky Family} type Characters gain +2000 power during this turn. Then, for the rest of this turn, you cannot play more Stage cards.
Sea Train
Purple Stage
Cost 6
{Water Seven}
[On Play] DON!! -1: Play up to 1 Character card with the original name “Franky” or “Iceburg” and a cost of 7 or less from your trash. Then, for the rest of this turn, you cannot play Character cards from your hand.
And characters like:
Franky
Black Character
7 Cost / 7000 Power (Strike)
Counter +0
{Water Seven} / {Franky Family}
[On Play] You may add up to 1 {Water Seven} type Stage card from your trash to your hand. Then, trash 1 card from your hand.
[Activate: Main] [Once Per Turn] If this Character was played this turn, you may rest this Character: Play up to 1 {Water Seven} or {Franky Family} type Character card with a cost of 3 or less from your trash. Give that Character [Rush] during this turn. At the end of this turn, that Character’s power becomes 0 until the end of your opponent’s next turn.
Iceburg
Black Character
7 Cost / 2000 Power (Wisdom)
Counter +2000
{Water Seven}
[Activate: Main] You may trash this Character: Up to 1 of your opponent’s Characters gets -6 cost during this turn. Then, you may return 1 Stage card on the field to its owner’s hand. If the returned Stage had a cost of 4 or more, KO up to 1 of your opponent’s Characters with a cost of 2 or less.
Kiwi & Mozu
Purple Character
3 Cost / 4000 Power (Slash)
Counter +0
{Franky Family}
[Activate: Main] [Once Per Turn] If your Leader is [Franky], add up to 1 DON!! card from your DON!! deck to your field rested.
Kokoro
Purple Character
1 Cost / 0 Power (Wisdom)
Counter +2000
[On Play] Trash 1 card from your hand. Then, return up to 1 Stage card on the field to its owner’s hand.
Tom
Black Character
5 Cost / 6000 Power (Wisdom)
[Opponent’s Turn] All of your [Franky] and [Iceburg] Characters gain +3000 power.
[Blocker]
[On Play] You may trash 1 {Water Seven} Stage card from your hand: Draw 2 cards.
And maybe an event that takes advantage of the fact that the Character you give Rush with Franky will end up at 0 power:
Water Seven Event
Black Event
Cost 2
[Main] If your Leader is [Franky], you may trash 1 of your Characters: Draw 3 cards. Then, play up to 1 {Franky Family} or {Water Seven} type Character card with a cost of 1 from your hand.
Something along those lines. Maybe some of these cards sound a bit too strong or not fully refined, but I think as a concept it could actually be something really unique for the game, especially with a Stage-focused engine and a Water Seven / Franky Family identity.