do you know any (theoretical or empirical) recent famous paper about monetary unions ? I heard that topics like "monetary unions at ZLB" or "fiscal coordination during crisis time" are quite popular these days.
Get a copy of De Grauwe's "Economics of Monetary Union". The most recent version (13th edition) is quite recent, from this year. So if there is a "famous" recent paper, it is discussed in there. The book is certainly more guided than searching for recent papers that cite Robert Mundell.
My original answer did not point to a recent "famous" paper so this is an edit. One recent paper that looks interesting, but probably is not "famous", relates to the subject of rollover risk in a currency region. The title is "Coordination and Crisis in Monetary Unions". This can be discovered via keyword search. I do not know how one would find recent "famous" papers except to keyword search the most popular and highly respected economic journals.