I'm in EP4 and I think I'm getting close to the end of the episode but I still haven't found all the tarot cards. If the cards I have are already useable I might skip finding the rest.

there are only 2. Would be cool to know when the set is complete. I was confused like you but I'm happy I don't care about that part of the game. So I just finished the level with the two cards I had and it turns out I found them all.

There's a card for every type of attack the Presence can throw at you. You need to find five specific items and trade them in at the confession booth.

One is found inside the crypt you enter through the well. It's inside the room with the monster as you try to solve the riddle.
The second is inside the basilika, right near the hatch you use to enter it the first time.
The third is hidden behind the rusted doors at the skriptorium-
The fourth is inside one of the mausoleums at the graveyard. The door will only open close to finishing the chapter.
The fifth and last one is inside the shack of the graveyard. The sculpture in the backroom is holding it.

The complete set is five cards.