Suggestions by @maxthecat67

Abbott and Costello

as Arry and Bert in Thomas the Tank Engine (1952)

Adriana Caselotti

as Emily the Stirling Engine in Thomas the Tank Engine (1952)

Gregory Peck

as Stanley the Silver Engine in Thomas the Tank Engine (1952)

Basil Rathbone

as Oliver the Great Western Engine in Thomas the Tank Engine (1952)

Nigel Bruce

as Duck the Great Western Engine in Thomas the Tank Engine (1952)

J. Pat O'Malley

as Bill and Ben in Thomas the Tank Engine (1952)

Vincent Price

as Diesel in Thomas the Tank Engine (1952)

Peter Lorre

as Toad the Brakevan in Thomas the Tank Engine (1952)

Basil Rathbone

as Oliver the Great Western Railway in Thomas the Tank Engine (1952)

Alan Menken

as Composer in Poppy Playtime (1991-1995)

Gary Goldman

as Writer in Poppy Playtime (1991-1995)

Don Bluth

as Writer in Poppy Playtime (1991-1995)

Gary Goldman

as Producer in Poppy Playtime (1991-1995)

Don Bluth

as Producer in Poppy Playtime (1991-1995)

Steven Spielberg

as Executive Producer in Poppy Playtime (1991-1995)

Gary Goldman

as Assistant Director in Poppy Playtime (1991-1995)

Don Bluth

as Director in Poppy Playtime (1991-1995)

Robert Urquhart

as Douglas in Thomas the Tank Engine (1952)

James Donald

as Donald in Thomas the Tank Engine (1952)

Dick Van Dyke

as Duck the Great Western Railway Engine in Thomas the Tank Engine (1952)