This article is from the Enya FAQ, by Kevin Martin enyafaq@brasscannon.org with numerous contributions by others.
Quite a few:
1983 Mairead Ni Mhaonaigh & Frankie Kennedy / Ceol Aduaidh
Synthesizer on track An Clar Bog Deil. The duo later formed
the folk band Altan.
1985 Christy Moore / Ordinary Man
Keyboards and backing vocals. Also credited as one of the
album's arrangers.
1987 Sinead O'Connor / The Lion And The Cobra
Spoken passage from the Bible (Psalms 91:11-13), in Irish,
on the track "Never Get Old."
1991 Terry Reid / The Driver
Recorded at London's Sarm West studios at the same time that
the Enya team were there mixing "Shepherd_Moons". The album
features several unaccredited guest artists, with Enya
providing a typical multi-tracked backing vocal on "The
Whole Of The Moon." Any other contributions from her are
less obvious.
1996 Clannad / Celtic Folk Festival
This album features works by various artists including two
previously unreleased tracks by Clannad from the period when
Enya was a member of the band. Horo Gheallaid and Dulaman
were recorded live at the Muziekcentrum Vredenburg Folk
Festival at Utrecht, Holland, on 13 February 1982.
 
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