all of them
1st one is in front of the market hall with all the bottles.
2nd one is in the gloomy forest cave.
3rd one is in the beach cave's first area, in one of the rooms there.
4th one is in the southern parts logwoods, the forest after logtown with morca.
5th one is in the fire dungeon, 2nd floor in one of the later rooms, just before the 2nd boss of the dungeon.
6th one is currently only in the patreon build, on the new island.