KingJoker
Author, how about another Island where there is another Logia fruit Cloud-Cloud fruit. I already have several moves for this fruit like, it can change to various elements like Lightning Strike, Hailstorm, Rain, Acid Rain. The user can even float aimlessly and Immune to most attack of Logia users except Magma
Maybe ancient city in the cloud island like Vegapunks in the last chapters. Which have some technologies for working with metal for ships? Or laboratory with some devil fruits like Salt-Salt(very similar with sand-sand from crocodile with taking water from opponents body(like ocean water for river fish) but for their cook) also can be some ancient robots that works and weapons. Also may find some notes on poneglyphs language.