Here is a breakdown of the other actors who appeared in multiple AFI 100 movies:
Robert De Niro - 6 appearances
Meryl Streep - 6 appearances
Dustin Hoffman - 5 appearances
Gene Kelly - 5 appearances
Spencer Tracy - 5 appearances
Marlon Brando - 4 appearances
Al Pacino - 4 appearances
Tom Hanks - 4 appearances
Katharine Hepburn - 4 appearances
Judy Garland - 3 appearances
Cary Grant - 3 appearances
Paul Newman - 3 appearances
Sidney Poitier - 3 appearances
Denzel Washington - 3 appearances
Note that these numbers are based on the original AFI 100 list, which was published in 1998. Some of these actors may have appeared in additional AFI 100 movies that were released after 1998.