If Thomas were...

Mr Men
James - Mr. Tickle

Rocky - Mr. Greedy

Thomas - Mr. Happy

Lady - Miss Sunshine

Gordon - Mr. Grumpy

Diesel - Mr. Rude

Percy - Mr. Small in the Oringal Mr Men Series

Bill - Mr. Small in the 2008 series

Daisy - Miss Naughty [Daisy and Miss Naughty play tricks]

Emily - Miss Chatterbox

Donald and Douglas - Mr. Scatterbrain

Stepney - Mr. Nosey in the Oringal Mr Men Series

Ben - Mr. Nosey in the 2008 series

and more

Mario
Thomas - Mario

Oliver - Luigi

Percy - Yohisi

Duck - Wario

Diesel - Bowesr

and more

South Park
Thomas - Stan

Duncan - Kenny

Duck - Kyle

Timmy Turner from the Fairly Oddparents - Cartman

and more

The Simpsons
Thomas - Homer

James - Bart

and more

Barney
Toby - Barney

Mavis - Baby Bop

Derek - BJ

Thomas - Micheal

and more

Looney Tunes
Thomas - Bugs Bunny

Gordon - Daffy Duck

Percy - Tweety

and more

Spongebob
Thomas - Spongebob

Percy - Patrick

Henry - Squidward

Emily - Sandy

Diesel - Plankton

Salty - Mr. Krabs

Molly - Mrs. Puff

Duck - Larry

Diesel 10 - the tough fish

and more

Family Guy
Henry - Peter

Emily - Louis

James - Chris

Duck - Brain

Diesel - Stewie

and more

Toy Story
Thomas - Woody

Percy - Buzz Lighter

Toby - Mr. Potato Head

Diesel 10 - Evil Emper Zurg

and more

Cars
Thomas - Lighting McQueen

Diesel - Chick Hecks

Terence - Mater

and more