>>532598252
Book of Moon and Eclipse since you can use them to dodge imperm/veiler and still contact fuse, and also they combo with Dancing Leaves. Karma Cannon because Ninjas aren't good enough to build "fairly" to maximize consistency and need blowout cards to make sure that they actually win when they go first.
Unless you want to play a warriorslop deck that has some ninjas in it you won't find much that actually synergizes well with them. The way they work you want to maximize your odds of opening two card combos since you won't be finding Hanzo every game.