There's a
plethora of
J.R.R. Tolkien works besides
The Lord of The Rings and
The Silmarillion, although most of them are in various stages of completeness. The Lays of Beleriand is one of these.
It contains two long poems. The first tells the tale of Turin Turambar in unrhymed alliterative verse. The tragedy of Turin was in a constant state of revision over time, and Christopher Tolkien includes two different manuscripts that his father wrote. The lays are markedly different than the versions we are later given in The Silmarillion. Among the most notable differences is that Gwindor is referred to as Flinding, son of Fuilin, though that may simply be because it was alliterative with Frail Finduilas, Fleet and Fair.
The other poem is about Beren and Luthien, a favorite tale of Tolkien's that appears in The Lord of The Rings as well as The Silmarillion. It is presented in a series of rhymed couplets. Included is some commentary and criticism by C.S. Lewis, who was known to have admired Tolkien.