The straw hats were simply sailing the seas to Morioh yet they landed in unknown island that isn't in da map, where supposedly there were various things they seek

Zoro: seeks for another sword just to test

Luffy: was seeks for food, obviously

Nami: was obviously seeks for treasures,money,and valuable things

Chopper: seek for a herb known for being a very good antidote for most things*

Robin for one of those stones only she can read

Usopp: seeks for some materials for bullets