I think it would be best to label pet blades and traps while in battle. Example: You have multiple blades in your deck and they all show up. In order to know which one is which I think we should add the pet sign on the card so we can know which one is which so we won't mess up on adding blades.
When your pet blades show up in your deck, you should be able to tell them apart from normal blades, for the cards are blue. Also, when you're in battle, you can put the mouse over your icon in battle (right to the left of your health) and it will show you which blades are which.