The Pokémon Company International has revealed several more cards for the Pokémon TCG: Pokémon GO special expansion. The first wave of expansion-related products will be available to purchase from July 1st. The Japanese equivalent subset, which will feature similar cards, will be released in Japan on June 17th.
Some cards will have a little Ditto icon in place of the typical tournament registration mark. These cards are actually Transformed Ditto cards. Players can peel off a layer of sticker from the card, revealing the actual Ditto card below. The Pokémon on the sticker layer can't be used competitively in official matches, only the Ditto itself is legal.
The official Japanese Pokémon Youtube channel has uploaded a video showing how to peel off the top layer.
The Japanese website has also revealed designs for Energy cards in this expansion, featuring the Pokémon GO logo on the bottom-right corner of the card. It is unknown at this stage if the English equivalent set will include these cards.