Named Allies:
- Radagast the Brown
- Tom Bombadil
- Goldberry
- Ents
- Fangorn "Treebeard"
- Finglas "Leaflock"
- Fladriff "Skinbark"
- Bregalad "Quickbeam"
- Fimbrithel (Entwife) (?)
- Elves*
- Haldir (?)
- Mithrellas (?)
- Maglor (Second son of Feanor)** (?)
- Old Man Willow
- The Mouth of Sauron (?)***
* Tolkien mentions that when Celeborn left Middle-earth "with him went the last living memory of the Elder Days in Middle-earth." Since this is written in the Appendices of the Lord of the Rings, and the Red Book was compiled in IV 172, this gives us a hard date for which all "living memories" of the Elder Days have left Middle-earth. In my game, I interpret this as meaning that only Silvan elves remain in Middle-earth; all of the Sindar and Noldor leave pretty soon after the War of the Ring.
** Maglor is the one exception to my "only Silvan Elves" rule -- his fate is unknown, save that after throwing the Silmaril in the sea he wandered the shores of the world, lamenting, and never returned to his people. It's a long shot, but he could feasibly still be around somewhere.
*** Realistically, the Mouth of Sauron probably died at the end of the War of the Ring. But, since we never actually hear what happened to him, so we can conjecture (however wildly) that he survived. Would he live for another two centuries, though? Perhaps if sorcery is involved?
[ADDENDUM: I suppose Findegil, the King's Writer who compiled the Red Book in IV172, could very well still be alive 48 years later in IV 220.]