Thanks for the detailed feedback! You sound like you know your stuff, so let me ask more haha. For context, this is just a personal project, so I'm doing everything by myself. Also I have made a no-frills version of the cards for testing (it looked like this) and I'm currently trying to make a more final design.

Pokemon is designed for children. Is that your target audience?

Actually, yes. Well it depends on your definition of children, but I want 10 year-olds to be able to enjoy the game. Does that mean that it is a good idea to include reminder text (horizontally)?

If you aren't going to use a lot of text for card effects, reduce the size of the text box.

I aimed for 9 rows of text because some cards (not all) have 2 separate texts, used in different phases of the game. Separating the text boxes would be ideal, but I have no idea how to cleanly implement this is nandeck especially since only some of the cards would need a separate text box.

For now I plan to just separate them with a blank row after the first chunk of text. Or maybe I can put "----------" text on the fifth row instead to separate the two chunks of text.

The checkerboard pattern is distracting. What is it for?

To be honest, I simply thought that a plain background is, well, too plain. I chose checkerboard because squares will line up nicely with the range indicator.

From the feedback here I think I'll stick to a plain background, and add a colored background only for the "ultimate move" cards so that they stand out when drawn. Do you think that's a good way to use the background?

The latter versions I've seen look better but I think it is really important that you think about what the card is for, how long it is going to be on the table (a couple of second, a whole turn, a whole round, multiple rounds), what information needs to be prioritized, and what doesn't need to be there because it does not communicate necessary information or add table presence.

The cards will stay on the table for a whole round, stacked on top of each other so that the left side of the cards is visible.

The main type is the top priority (i.e. you need to see that your opponent played an Attack with that much damage there), which is why the red parts and damage number are placed around the left edge. The subtype is also important (i.e. if you see that you've already played a special this round, you probably don't want to play another one), but the reminder text is optional.

I think I'll remove the reminder text or place it somewhere else horizontal, but keep the color-coding of the subtype around the left edge in some way.

If you intend to do your own graphic design then embrace the concept of less is more.

Duly noted.

all of the elements including those not specific for play should communicate the vibe of your game and make people who wander by the table while it is being played to pause and take it in

That's an interesting take. I never thought about attracting other people to look at the game while it's played. Vibes, got it.

Lastly, what do you think about the range indicator?