The adverb ᴱQ. are “beside, along” appeared in the Qenya Lexicon of the 1910s under the early root ᴱ√ƷARA “spread, extend sideways” (QL/32).
Neo-Quenya: Since the preposition ar(a) “beside” appeared in Tolkien’s later writings, I think ᴺQ. arë “beside, along, ✱near” can be retained as an adverbial form of that preposition.
A (deleted) adverb in the Qenya Lexicon of the 1910s glossed “in addition, as well, besides” under the early root ᴱ√ƷARA “spread, extend sideways” (QL/32).