In OP2 meta, the only blue deck that can stay noteworthy in this meta is Ivankov Impel Down deck. It is rather a straightforward but fun deck to play. Here is my version of Impel down, and I prefer to go first if possible.
The main combo
The main combo of the deck is, of course, play 7-cost Ivankov then got Luffy summoning for free.
Impel down blockers
There are 2 Impel Down blockers, Galdino and Inazuma. People normally likes to use Inazuma but I always prefer Galdino. Simply because I can use Galdino to attack then I make him active again at the end of the turn (by trashing 1 card from hand).
Galdino and Ivankov leader have the "End of Your Turn" effect which is same timing. There is the time when I have no card to trash to trigger Galdino effect, then I will use the Ivankov's effect to draw 2 cards then trash 1 to set Galdino active.