Some suggestions:
Manwe
Celebrimbor
Gil-Galad
Eärendil
That's all i could've think of
Unfortunately (or fortunately) the lore is very clear and 'nuclear' about proposals like yours.
Celebrimbor and Gil-galad have been dead for more than 3000 years by the time of the War of the Ring, and are thus either still mourning in the Halls of Mandos as spirits, or reborn in Valinor as Blessed Elves; they are anyway in Aman, and thus are bound to remain in this continent forever, as the 'supreme rule' of the World for the Elves ineluctably implies, and can't then be revived or return to Middle Earth (the spell 'The Last Alliance' only summons Gil-galad temporarily, and it is a tribute/reconstruction of the Second Age).
Anyone who reaches Aman, both due to Death (Halls of Mandos) or Return (Grey Havens), can't leave this land and return to Arda (apart from very few exceptions).
Eärendil is of course alive, as an immortal elf, but was ordered by the Valar to guard forever the Skyes of Arda and Aman with his Enchanted Ship, and thus can't go back to Middle Earth.
Manwë, eventually, is the most unlikely scenario, for very important and solid reasons.
- He is the King of the Valar and the King of the whole World, and he could virtually do and dispose anything he wants due to his absolute authority; but the Valar chose not to get directly involved anymore in the problems of Middle Earth, after the destructive (but victorious) War of Wrath, and chose not to personally fight anymore in any battle even before the First Age, since they sent an army of Vanyar and the Maia Eönwë in Beleriand.
The powers of the Valar is holy and good, but still destructive in war; if any of them fought in Middle Earth during the Third Age, it would cause a complete cataclysm.
- How in the world an evil and inferior (for a point of view of a Vala) object, as it is the One Ring, should summon Manwë (the Supreme Authority in the World), or even be worn by him?
- Manwë is a Vala, is not an Elf.
He is the leader of both Arda and Aman, but he truly 'belongs' to Valinor, the Blessed Realm in which live mostly Vanyar and Maiar; Imladris (Noldor) is, on the other way, related and 'belongs' to Eldamar (specifically Tirion), which is still a Land/Realm of Aman, but it is not Valinor.
I know that the difference would appear to be slight, but it is important.
Then, given these facts, the only 'reasonable' solution by far is still Elrond with the One Ring.
Hope to have been useful