As of now those are the only 48 cards, but it would be safe to assume that more will most likely be available later as DLC. Actually, I'm more surprised the new single "Chance no Junban" is not yet available as DLC.
1ST ROW PICTURE 1 - you have to finish with one girl but you have to reject all girls the others girl PICTURE 2 - unlocked when you start with that girl (Day 1) PICTURE 3 - you have to receive a present from the girl PICTURE 4 - Good ending with the girl PICTURE 5 - reject the girl in the first date (Day 1) PICTURE 6 - after rejecting the girl, you must receive an email date invite PICTURE 7 - reject the girl during the 2nd dating phase (2nd outfit) PICTURE 8 - accomplish all the scenarios during the second phase, Including the date that she asks you to meet the next day
2ND ROW PICTURE 1 - After the Credits, rapidly press L or R after your ending girl congratulates you (Encore) PICTURE 2 - give the girl 1 wonderful answer PICTURE 3 - On the 10h day you have to give a Wonderful answer to the girl PICTURE 4 - In the 20th day you have to give a Wonderful answer to the girl PICTURE 5 - Complete the girl with Good ending 3 Time (will have a big heart in the profile pic) PICTURE 6 - Receive a call from the girl, and give a good response PICTURE 7 - the girl should meet you in the city PICTURE 8 - Receive a voicemail from the girl, go on a date, and respond with a good answer
3RD ROW PICTURE 1 - ??? (get the bad ending?) PICTURE 2 - Answer her Birthday question correctly
also, chance no juban is already in the game, its in fact the game's theme song.