Thanks you Yog! I love to do some behind the sceen stuff. I'll write out the steps
This is edited file I use for the Holo effect:
https://image.ibb.co/iS0khn/Holo.png
1. The effect is added when everything else is done. Place the PNG in your photoshop document. Place it in front of the background, the card and the Pokémon. Behind all the text, icons (attack cost, weakness, set logo).
2. Change the opacity of the Holo effect to around 12%. The Holo effect PNG should be slightly bigger than the card.
3. Open the Timeline. This is when you start moving the Holo effect while adding frames. Show the Transform Controls to accurately move the Holo effect. When you moved the Holo effect all the way up or all the way down select all the frames and duplicate them. Place the duplicated frames behind the copied frames, then reverse them. This ensures the effect loops. If you want the effect to be smooth you should end with around 30 frames.
4. After you're finished with the frames, editing anything besides the Holo effect may result in objects moving unwanted. If for example you want to move the Pokémon slightly to the right, you should select all the frames before you do so. If by accident you forget, you can always select the frame where the object is in place. Convert the object to a Smart Object and it remains in place for all frames.
I hope this explanation is clear, if not I can always add a few screen shots.