Suggestions by @silverangvantibo

Lee Byung-hun

as Nightwielder in The Reckoners Trilogy

Colin Farrell

as Prof in The Reckoners Trilogy

Mark Strong

as Steelheart in The Reckoners Trilogy

Jane Levy

as Megan in The Reckoners Trilogy

John Carroll Lynch

as Fred Colon in Discworld

Michel Muller

as Nobby Nobbs in Discworld

Simon Helberg

as Cut-Me-Own-Throat Dibbler in Discworld

Roger Ashton-Griffiths

as Mustrum Ridcully in Discworld

Wallis Day

as Angua von Uberwald in Discworld

Tim Minchin

as Rincewind in Discworld

Edward Norton

as Lord Havelock Vetinari in Discworld

Jerome Flynn

as Samuel Vimes in Discworld

Dennis Quaid

as Samuel Vimes in Discworld

Michael Keaton

as The Consul in The Hyperion Cantos

Sigourney Weaver

as Meina Gladstone in The Hyperion Cantos

Daniel Dae Kim

as Het Masteen in The Hyperion Cantos

Gina Carano

as Brawne Lamia in The Hyperion Cantos

Bryan Cranston

as Sol Weintraub in The Hyperion Cantos