There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
iol
noun. lamb
gwenniniol
adjective. maiden(ly), girlish
A word in the Gnomish Lexicon of the 1910s appearing as {gwend(r)iol >>} gwenniniol “maiden (aj.), maidenly, girlish”, an adjectival form of {gwen >>} G. gwennin “girl” (GL/45).
elfrin(iol)
masculine name. Littleheart
-(i)ol
suffix. adjective suffix
ilfrin
masculine name. Littleheart
elfrith
proper name. Littleheart
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
The word G. iol “lamb” appeared in the Gnomish Lexicon of the 1910s (GL/51), clearly a cognate of ᴱQ. eule of the same meaning from the early root ᴱ√EWE (QL/36), since *eu* usually became *io* in Gnomish. G. iolinc “little lamb, lambkin” is a diminutive form (GL/51).
Neo-Sindarin: I would adapt this word as ᴺS. ŷl “lamb” for purposes of Neo-Sindarin, since *eu* usually became *ȳ* in Sindarin.