The long-running "Wano" arc of One Piece is finally about to reach its conclusion. Luffy and Kaido have entered the final stage of their fated battle and once it is over, the people of Wano will be free. The Straw Hats will likely have their big end-of-the-arc party that Luffy has been waiting for since before the raid -- but where will they be heading afterward?
Ever since they allied with Trafalgar Law on Punk Hazard, the Straw Hats have had a clear path ahead of them. They wanted to take down Kaido, so they had to cut off his supply chains for the Smile Fruits. That meant kidnapping Ceasar Clown, which then led to them destroying the Smile Factory and defeating Doflamingo on Dressrosa. Then they went to regroup on Zou, but Sanji was captured so they had to save him on Whole Cake Island before they could finally head to Wano.
One Piece's "Wano" arc has been similar to Alabasta, where the Straw Hats stopped on multiple islands on their way to help Vivi save her home. Other than their invasion of Big Mom's territory, which was bound to happen eventually seeing as she had a Road Poneglyph, the Straw Hats have been progressing toward the singular goal of beating Kaido. When Alabasta ended, they had no idea what their next adventure would be until the ship fell out of the sky and started the "Sky Island" saga. Since then, however, more of the outside world of One Piece has come into focus, and massive events have occurred that might draw the Straw Hats in.
The first is the fallout of the Reverie. Leaders from the nations affiliated with the World Government met and decided to disband the Shichibukai, so the now former Warlords are being hunted down. While they were in session, Sabo and a few of the other Revolutionary Army leaders got into a skirmish with the two admirals who were in Marijoa.
On top of all this, Big New Morgans announced that there was a death at the Reverie, implied to be either Sabo, Vivi or her father Cobra. Though it's unlikely that Vivi or Sabo would die, especially off-screen, there is the possibility that one or both have been captured. Sabo is a wanted criminal and Vivi's picture was in the hands of the mysterious Imu, the leader of the Five Elders, so both are targets whom the World Government would want to execute like they did to Ace. If the Straw Hats found out either one of them had been captured, they would surely race to save them.
Luffy did not go to save Ace when he first saw his vivre card was fading -- and that likely still haunts him to this day. Since Wano is isolated, however, it would be hard to learn any of this information, but there is a small fleet of Navy warships sitting just outside it. The crew could interrogate them or steal a newspaper on their way out.
Another option for their next island is Elbaf. If the Straw Hats don't learn about the news from the outside world and are left to their own devices, they could be heading toward the land of giants. Like Wano, Elbaf was mentioned very early on in One Piece -- all the way back in Little Garden -- and Usopp has made it a personal goal to visit this island. It could be a short arc like Zou, where the crew learns some valuable info that helps them decide where to go next. Giants like Oimo and Kashii could make an appearance, or maybe the Prince Loki will finally be revealed. After the mega-arc that is "Wano", it would be nice to wind down with a small relaxing storyline before heading into the endgame.
The Straw Hats could also end up on God Valley. The mysterious island was first mentioned just before Act 3 of Wano began, when Sengoku told the tale of how Monkey D. Garp became the Hero of the Navy. The island is no longer on any map, but if the Straw Hats got close to it then Nami would surely realize there was one nearby.
The Straw Hats' navigator also has a wish to draw a map of the world, so finding an island that's not on any map would be a real treat for her. They would likely uncover some information about the Rocks Pirates and the World Nobles here, and shed some light on the God Valley Incident that occurred 38 years ago.
There are sure to be more clues for the future coming as One Piece's "Wano" arc winds down, but for now the window of possibilities remains wide open. No matter where they go, the Straw Hats will soon be one step closer to Laugh Tale.