This page is a complete list of every Gold Hoarder riddle clue that I know about.
The list is still far from complete, but growing all the time.
A Gold Hoarder riddle sheet contains three types of clue, which are revealed one by one, as you solve them:
May clues contain a phrase that indicate that the landmark is underground, that is, in a cave. These phrases vary, depending on the action you must take when you get there. For example:
Click on an island name, below, to open the list of key phrases indicating landmarks on the island. These key phrases will be woven into clues, often in the form of rhyming couplets. Click on the phrase itself to see a map and screenshot. Click on these for a bigger view. The screenshots are designed to show the landmark at its best. For most landmarks, especially larger ones, you will have to move closer than the point from which the screenshot was taken.
human skeleton / skulls: This guy is a skeleton to the left of the "forbidden tomes" in "the cavern below Cannon Peak"
location: Stand in the middle of a grove of trees, underneath the prominent tip of rock of Cannon Peak. The precise location can be hard to get right. You need to look up through the trees.
tree(s) or rock(s): in the cave system, in the side cavern, on the North side of "the wooden bridge"
human skeleton / skulls: Enter the cave opposite the jetty, and proceed straight ahead into the chamber with the Endless Lizard painting and the cavern campfire.
campsite / fire: Enter the cave opposite the jetty, and proceed straight ahead into the chamber with the Endless Lizard painting and the "cavern camp's forgotten prisoner"
rock painting: Enter the cave opposite the jetty, and proceed straight ahead into the chamber with the cavern campfire and the nearby "forgotten prisoner"
rock painting: As you come to the top of the wooden stairs on the Eastern side of the island, this is a little way to the left.
human skeleton / skulls: The X marks the entrance to "the overgrown entrance to the North cave". Follow the passage in
grave: The burning skull grave is the one to the left in the screenshot, with a small flame in the upturned skull.
location: This can be hard to find. If you approach the arch from the Northern side, look for a crevice in the rock on the left-hand side as you enter the arch.
tree(s) or rock(s): Two leafless trees, with their branches tangled, and a flame in a pot, suspended between them.