Suggestions by @sadsamurai

Ido Mosseri

as Pastor Mightily Oats in Carpe Jugulum

Score: +1

Paul Telfer

as King Verence II in Carpe Jugulum

Score: +1

Kelly Macdonald

as Queen Magrat Garlick in Carpe Jugulum

Score: +1

Alec Secăreanu

as Count Magpyr in Carpe Jugulum

Score: +1

Rachel Griffiths

as Neilette in The Last Continent

Score: +1

Ben Mendelsohn

as Letitia in The Last Continent

Score: +1

Jai Courtney

as Darleen in The Last Continent

Score: +1

Richard Dawkins

as The God of Evolution in The Last Continent

Score: +1

Maggie Smith

as Mrs. Whitlow in The Last Continent

Score: +1

Karin Konoval

as The Librarian in The Last Continent

Score: +1

Daniel Radcliffe

as Ponder Stibbons in The Last Continent

Score: +1

Hugh Grant

as The Senior Wrangler in The Last Continent

Score: +1

Jeremy Irons

as The Lecturer in Recent Runes in The Last Continent

Score: +1

Gary Oldman

as The Chair of Indefinite Studies in The Last Continent

Score: +1

Michael Rosen

as The Bursar in The Last Continent

Score: +1

Brian Blessed

as Henry in The Last Continent

Score: +1

David Jason

as Mustrum Ridcully in The Last Continent

Score: +1

Mel Gibson

as Scrappy the Kangaroo in The Last Continent

Score: +1

Lee Mack

as Rincewind in The Last Continent

Score: +1

Jean Reno

as Leonard of Quirm in Jingo

Score: +1