Salomey

Possible members are Vegapunk Lillith, Yamato, Loki and Vivi.

1. There is a vegapunk at weatheria that leaves lillith to wander for the time being, gathering information. And it would be a plus for a vegapunk to be at Laugh Tale during the revelation.

2. Yamato's invitation was approved which makes her a partial member of the straw hats. She is just on a hiatus and with her will to travel around, staying in wano won't be ideal. Joining the straw hats is the way to go.

3. Unless Loki is made the king of Wano, his dreams of pulling a Ragnarok and rebel against the WG suits him joining the straw hats. Plus his joy boy affiliation and dreams, would make him be around Luffy. Plus I see wano burning and the Adam tree being used to create a new ship maybe to house loki on the sunny.

The above three all have the necessary power level and resources to push the straw hats beyond their current level.

4. Vivi's affiliation to the D puts her in on the run mode. Hence, her royalty to Alabaster, will be placed in danger leaving her to join the straw hats till the day of War. So she is a very formidable ally as her royalty will bring in more nations.