St Malachy was an Irish bishop who died in 1148. He predicted all the future popes, not by name but by some characteristic of theirs. He did however name the last pope in his list who he said will be called Peter. There’s only one more pope left (after the current one) according to the list so the next one will be Peter, the last one:
Previous popes were described thus:
Benedict - The glory of the olive. The Order of Saint Benedict use an olive banch as part of their symbol
John Paul II - De Labore Solis (from the toil of the sun). He was born and was buried on the day of a solar eclipse.
John Paul I - De Medietate Lunae (of the average age of the moon). His papacy lasted only 34 days. About one moon cycle.
Paul VI - Flos Florum (flower of flowers). His personal arms bore three fleur-de-lis
Bishop Malachy supposedly described the next 112 Popes after the incumbent Innocent II. Benedict XVI is only the 101st Pope since then (“Crux de Cruce”) so we’re still safe for ten more Popes.
I like X or Z names, but it would be appropriate to pick a name that is a Catholic Saint to make sure you aren’t accused of making fun of the papacy, so I would be Pope Xystus or Pope Zoticus (I can’t believe, after checking at Catholic Online, how many St. Zoticuses there have been!)
Pope Xystus is much the better of the two names. The name itself, and the X starting it, seem like it could give rise to all kinds of mystical conspiracy theories or biblical predictions or whatnot. It just sounds so mysterious.
ETA: to appease the believers in the prediction of St. Malachy, I’ll choose a compound or double-barrelled name like Jean-Paul I and Jean-Paul II did: Xystus-Pierre (French) aka Xystus Peter (English).
(I wonder why those hyphenated first names have caught on in French but never in English.)