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Yes, there have been several. Salza & Siscoe's True or False Pope (1st ed.) pp. 7-8:
Mirko Fabris (d. 2012), a stand-up comedian from Croatia, was elected by a "Conclave" in 1978 and became "Pope" Krav (his stage name). David Bawden, a seminary drop-out who lives with his mother in a farmhouse in Kansas, was elected "Pope" Michael by six lay people including his parents in 1990. During his "reign," Bawden has had to compete with various other Sedevacantist groups who have elected their own "Popes" β namely, Linus II (in 1994), Pius XIII (in 1998), Leo XIV (in 2006), Innocent XIV (in 2007), and Alexander IX (in 2007). Still other Sedevacantists have simply declared themselves Pope without an election, even claiming their election came from Heaven itself, such as Gregory XVII (in 1968), Emmanuel (in 1973), another Gregory XVII (in 1978), Peter II (1980), Gregory XIV (in 1983), another Peter II (in 1995), yet another Peter II (in 2005), Gregory XVIII (in 2011), and John Paul III (in 2015), among others.
David Bawden ("Pope Michael I") from Kansas is one such anti-pope. He has no apostolic succession, being invalidly elected by a conclave comprised of laymen, including his parents and four others. Pope Michael: A Documentary Film is free to watch online.
Conclavists are sedevacantists who elect their own popes.