The original Angel of Mercy appeared in Portal Second Age, in 1998.
The original art was by Melissa A. Benson.
The List
Jumpstart
Iconic Masters
Duel Decks Anthology: Divine vs. Demonic
Duel Decks: Divine vs. Demonic
Tenth Edition
Tenth Edition
Ninth Edition
Eighth Edition
Eighth Edition
Invasion
Starter 1999