GGAD video I watched.
GG: Gellert Grindelwald.
Actor:
Young GG: Jamie Campbell Bower, whose main works include "Sweeney Todd", "Rock and Roll", "Holy Grail Artifact: City of Bones", etc.
AD: Albus Dumbledore
Actor:
Young AD: Toby Regbo, whose main works include "The Man with No Name", "Pain is Blessing", "Treasure Island", "Queen of the Wind", etc.
Aged AD: Michael Gambon.
Ranking without distinction