Pokémon GO Trainer Customization
There are currently 7 possible customizations you can apply to your Pokémon trainer in Pokémon Go. Trainer Customization Options are called Customization Slots in the codebase.
The Unlockable and Payed Customizations are not yet available, even though they were introduced in the 0.49.1 APK (December, 2016). The same applies for various filters these customizations can have.