The Classics theme refers to the characters in their normal liveries.
- Iron Bert
- Diesel 10
- Troublesome Truck
The Core Moments theme features engines based off of famous incidents from stories.
The Graffiti theme featured engines covered in graffiti.
The Creature theme features characters as various animals.
The Sports theme features engines designed as different sports balls.
The Sweets theme features engines designed as confectionery.
The Electrified theme features engines with electricity and lightning designs.
The Racing theme features engines with racing car inspired designs. Three of the engines are re-releases from 2015.
The Spooky theme contains engines dressed up as scary and Halloween-like characters. Three of the engines are re-releases from 2015.
DC Super Friends
DC Super Friends is a theme which features engines dressed up as DC Comics superheroes or villains.
- Flynn as Firestorm
- Belle as Raven
- Victor as Hawkman
- Rosie as Supergirl
- Luke as Beast Boy
- Emily as Wonder Woman
- Salty as Aquaman
- Edward as Black Adam
The Tootsie theme features engines in the colours of Tootsie Roll Industries candy wrappers. They are only released in the US and Canada.
- Dots Thomas
- Fruit Chews Henry
- Blow Pop James
- Tootsie Roll Percy
- Sugar Daddy Toby
- Junior Mints Emily
- Double Bubble Gordon (cancelled)
- In Japan, a collector card of each character featuring a QR code is included in a blind bag.
- During Series 4, some numbers have changed.
- On the Series 1-2 checklist, Spooky Salty is shown instead of Spooky Emily.
- On the Series 3-4 checklist, Rosie as Hawkgirl is shown instead of Victor as Hawkman.