Rings

Working assumption/theory is that they returned to their original location post-Ragnarok.

Originally (pre-Lastar), there were seven rings of power amongst the second born (Dwarves) and four separate Elven gems, which contained elemental power (the Dwarven rings and the Elven Gems were linked to Planes and/or elements)

At Lastar's behest Orodruin combined the four elven gems with their aligned dwarven rings to create stronger artefacts. Moreover, they were at their strongest when all four were worn by the same person.

The remaining three Dwarven rings remained unaltered {"they (dwarves) shall keep them for their powers affect the (shall we say) less predictable domains that come into contact with the Prime"}

Two of the unaltered rings were positive and negative; the third is believed to be linked to the Astral. It would not be surprising if there was also an eighth ring linked to the Ethereal.

Ring and Gem combos:

Fire - Morgul (before gate swapped with Tiris)

Earth - Aarda

Air - Emras

Water - Tiris (before gate swapped with Morgul)

Ring only

Astral - Maedus

Negative - Zundar

Positive - Olga (the crown was there) {Alt: Malek(?) or Blaven's Pool (?)}

Ethereal - Olga ?? speculative - never recorded in prior history