Verse 16 begins the description of what it meant for a Jaredite to “become exceedingly rich.” Verse 20 confirms that the reason is that they were living according to the commandments, and therefore God kept his part of the covenant and blessed them in the land.
Most of the definition of wealth concerns things that are required for a basic living. There was food, both of grains and of kept animals, “which were useful for the food of man.” There are also things above simple subsistence. They do have silks, linen, gold, silver, and other precious things.
Interestingly, they have animals called cureloms and cumoms. There is no indication what those animals might have been, save that they were apparently particularly useful. It is also not known why these animal names were transliterated, while the others were translated. It might be related to the fact that the original names might have been known in the Jaredite language, but not in the Nephite language into which Mosiah translated.