There are plenty of accessories in Pokémon TCG Pocket to customize your experience, either as a collector or a player.
Here's a list of all the available accessories and how to obtain them.
Icons
Icons are used as your profile picture.
Playmat
Playmats are board mats that appear on the field during your turn. When it's your opponent's turn, the board flips to display their playmat and so on. Can be changed in the deck edition.
Card sleeves
Card sleeves are used to decorate the backs of your cards. Can be changed in the deck edition.
Coins
Coins are used whenever a coin flipping effect is used, and to decide who's starting the game. Can be changed in the deck edition.
Covers
Binder covers give a nice brush to your collecting binders. Can be selected when creating or editing a binder.
Backdrops
Display Boards backdrops can be selected when creating a display board for one of your card.