Live Mike
2438

Given the partial list of antipopes & interregna, should we be surprised to see another in our day? "What's past is prologue."

Natalius - antipope? (199-200)
St. Hippolytus of Rome - antipope (217-235)
Novatian, Latin Novatianus - antipope (251-251)
Felix (II) - antipope (355-358)
Ursinus - antipope (366-367)
Eulalius - antipope (418-419)
Laurentius, English Lawrence - antipope in 498 and from 501 to about 505/507
Dioscorus - pope or antipope, for 23 days in 530
Theodore - antipope from 21 September to 15 December 687
Paschal (I) - antipope against both the rival antipope Theodore and the legitimate pope St. Sergius I during 687
Constantine (II) - antipope (767-768)
Philip - antipope in July 768
John - antipope (844-844)
Anastasius the Librarian, Latin Anastasius Bibliothecarius - antipope (855-855)
Christopher - antipope (903-904)
Leo VIII - pope, or antipope, from 963 to 965
Boniface VII - pope, or antipope, from June to July 974 and from August 984 to July 985
John XVI - antipope (997-998)
Gregory (VI) - antipope (1012-1012)
Benedict (X) - antipope (1058-1059)
Honorius (II) - antipope (1061-1064)
Clement (III) - antipope (1080-1100)
Theodoric - antipope (1100-1102)
Albert, also called Adalbert or Aleric - antipope (1102-1102)
Sylvester (IV) - antipope (1105-1111)
Gregory (VIII) - antipope (1118-1121)
Celestine (II) - antipope (1124-1124)
Anacletus (II) - antipope (1130-1138)
Victor (IV), original name Gregory Conti - antipope (1138-1138)
Victor (IV), original name Ottaviano De Monticelli - antipope (1159-1164)
Paschal (III) - antipope (1164 to 1168)
Calixtus (III) - antipope (1168-1178)
Innocent (III) - antipope (1179-1180)
* Interregnum - Sede vacante (29 November 1268 - 1 September 1271)
[2 years, 276 days]
* Interregnum - Sede vacante (4 April 1292 - 5 July 1294)
[2 years, 92 days]
* Interregnum - Sede vacante (20 April 1314 - 7 August 1316)
[2 years, 79 days]
Nicholas (V) - antipope (1328-1330)
Clement (VII) - antipope (1378-1394)
Benedict (XIII) - antipope (1394-1423)
Alexander (V) - antipope (1409-1410)
John (XXIII) - antipope (1410-1415)
* Interregnum - Sede vacante (4 July 1415 - 11 November 1417)
[2 years, 136 days]
Clement (VIII) - antipope (1423-1429)
Felix (V) also called Amadeus VIII of Savoy - antipope (1439-1449)
* Interregnum - Sede vacante (29 August 1799 - 14 March 1800)
[197 days]

Sources:
Papacy - Popes, Antipopes, Succession |
List of popes - Wikipedia |
CATHOLIC ENCYCLOPEDIA: List of Popes |
Public domain
Ave Crux
God will make everything known at the time He has chosen. I find great comfort in knowing that any given Pope is not THE Church. And should we ever find ourselves in an interregnum -- or should a Pope ever abandon that which was handed down to him to preserve -- we simply do not follow him into error. We remain in place, unmoved and unmovable.
A Pope merely holds the place of Christ at the Head …More
God will make everything known at the time He has chosen. I find great comfort in knowing that any given Pope is not THE Church. And should we ever find ourselves in an interregnum -- or should a Pope ever abandon that which was handed down to him to preserve -- we simply do not follow him into error. We remain in place, unmoved and unmovable.

A Pope merely holds the place of Christ at the Head of the Church and the Mystical Body....and should the See be vacant, it doesn't change what we know and must live as concerns our precious Faith.

We know what we have received from the Church of the Ages, and it this which we preserve and cleave to. If any Popes abandon this, we stay firm and clear-minded in the Deposit of Faith and the Traditions we have received. In so doing so we can never be mistaken.
Live Mike
Note: Thus far, God has never allowed an interregnum to go on beyond 2 Years, 276 Days. There are some who claim that we have been in a period of interregnum since 31 December 2022 [1 Year, 37 Days and counting]