The Art Gatcha Cards are basically a nice little gimmick to reward you for the cruel task of SOCIALIZING in Hello Charlotte EP2. They can pretty much drop at random (or not at all) after the battles and come in 3 Varieties: Rare (R), Super Rare (SR) and Ultra Rare (UR). This determines how likely they are to drop. There is another way to get them, namely out of these little boxes:

There are 13 of the boxes in total, all in the same section of the game. Just interact with them and choose the second option to get a card. You can get several versions of the same cards, although they all disappear when you use one of them.
So what do these mysterious cards do?
Well, they show little pictures and sketches of the characters in the game and that's pretty much it. After that, the card disappears and there is no effect on the gameplay whatsoever.
But as someone who is a fan of the art of this game, I found myself spending quite a bit of time on finding as many different ones as I could and thought I could spare others a similar fate by archiving them.
I'm not in any way sure that these are all the cards you can get, these are simply all the ones that I could find after quite a lot of trying. If you found one that I missed, please message me!

So, here they are!

1. Night Gaming

This looks like so much fun, honestly. Sometimes it can be a lot of fun to just watch others play a game, especially if they're colourful characters. Like a chainsaw-wielding soap-addict and a tsundere mad scientist. Even though they're in black and white in this picture (I think I'll shut up now).

2. Don't Hinder

This one is less fun. Poor Charlotte. Living surrounded by all of these unusual people can be entertaining, but it sure has it's downsides. And even if Umbrella Man isn't keeping her up and Bennet isn't burning down her kitchen, the Oracle pretty much makes sure that she won't sleep peacefully.

3. Bennett

He looks so sad in this one. No wonder with his backstory, though. It's kind of a (soap-fueled) miracle that he can seem so happy most of the time. I also like how is cheek-eyes always emote along with him a little.

4. Infirmary

Oh Charlotte... She really goes through hell in this game. It's always painful to see someone who tries so hard to be happy so depressed.

It's honestly a little weird that there are no "Common" cards, but considering what these games usually have to say about marketing etc. that could be a statement.

1. Felix

The poor guy looks so traumatized! I developed a serious bit of older-sibling-instinct towards Felix in the first game, so it kind of broke my heart to see the way he became in the second. Although I still like him, of course.

2. Sleeping

And this is part of why. He can still be so adorable sometimes! And Charlotte still tries her best to rebuild their rapport. She really does love to be part of Brooding-Boy-Gentle-Girl-Dynamics, haha.

3. Umbrella Boy

Another cute one to balance out the sadness!
I always enjoyed the Umbrella Man as this mysterious Wild Card character. He never really helped Charlotte out, nor did he do anything to oppose her, but he does have his moments of kindness.

1. Landfill 1

So here we have a younger Felix and... I think that's Florence, given the smile. Interesting, considering that I don't think we ever see them interact in this game and not that much in the next one. Although there is much potential for comedy with their polar opposite personalities, so... Maybe that was cut? Or it is just part of the backstory? Ah, whatever, this picture is adorable.
UPDATE: Apparently, the girl is Charlotte from an alternate concept for Episode 2! The clothing style really makes a difference, lol. She looks so tough!

2. Landfill 2

Is this Florence again? Or another character I just don't recognize? I'm honestly not sure. But if it is Florence, my goodness girl, good job hiding all of that hair in your protection suit. And not tripping over it with every second step you take. And taking care of it at all, it must take hours.
But beside that, it would sure be fun to see all of the characters play baseball together! Although some of them would probably not be very good at it, haha.
UPDATE: This is another alternate Charlotte. Now I'm actually kind of interested in what that story would have been like, it looks so very unlike what we got in the end.

3. Landfill 3

Florence and Felix again. I think, at least. I wonder if he had to patch her and the others up a lot when he was younger. It seems to have become a natural thing for him by now, given his hilarious scene with Bennett. He always pretends not to care about the people around him but ends up helping them because he can't stand to see them in trouble. Which is adorable, but he still has a long way to go as a doctor.

These are all in colour. It's what makes them Ultra Rare, I guess.

1. Medusa

This one looks quite ominous, but aside from some foreshadowing for the end of the game, I'm not really sure what the image or the title mean. I guess the latter could symbolize isolation and transformation into a "monster" due to something that wasn't really one's fault (which somewhat describes the stories of both Medusa and Charlotte), but I'm not really sure what the jellyfish represents.

2. Midnight Train

I think this might be a reference to Spirited Away, with Charlotte as Chihiro and... the Oracle (?) as No-Face. Or maybe I'm just stupid. But either way, one of the things that make Charlotte interesting as a main character is her very casual reaction to decidedly abnormal and frightening things. I think that this picture represents that very well.

3. Young Gods

Vincent/C is definitely my favourite character in all 3 games and the way he just accepts Charlotte and her worldviews in this game is definitely part of the reason. And the way Charlotte accepts his quirks and stories in turn is part of what I like about her. In general, their dynamic and how well this game pulled off the classical social-outcast-friendship-plot is one of my favourite aspects of Episode 2.

So, well, thank you for reading.
Again, if you found a card I missed, please contact me about it. I myself will be adding any additional cards I may find on future playthroughs.
Have a nice day!