Tolkien's Legendarium - enough already or would you like more?
I can't see what else could be published but I feel Harper Collins always seem to come up with something? Maybe it's got to the point where absolutely everything will have been published.
The Hobbit (first three editions are all different)
LOTR (first two editions are different)
The above also available in annotated, illustrated, author illustrated and revised editions. Also in boxset edition with Readers Companion.
Bilbo's last song
The Adventures of Tom Bombadil
The Silmarillion
Unfinished Tales
History of Middle Earth (12 vols)
History of The Hobbit (2 vols)
The Nature of Middle Eartb
The Children of Hurin
The Fall of Gondolin
Beren & Luthien
The Fall of Numenor (compilation of previously published texts)
Letters
Letters (revised edition with more letters, upcoming in 2025)
Is there anything else out there that Harper Collins could publish to generate more money for the estate?