Out of these, I only own the garden's trowel. Only worth it, if you are planning to grow plants in the long run. Otherwise, best to skip as this item does not seem to be in high demand. It make seed organization easier and the seed list can be arranged by either (1) "color" and/or (2) "Bright?".
Garden's trowel can hold:
-water
-Greater cure/heal/poison/strength potions
-plant bowl
-fertile dirt
-100,000 seeds
Going back to your original question, it seems the jewelry key sells for a lot.