Just got my last illustration card. The last card probably unlocked after 10 more rounds. Really hadn't that much problems. Played about 150-200 arcade rounds for all 50. Didn't really looked at the screens and watched stuff for most of the time.
Now just onto the last weapon cards. At least that's not luck based.
1st on x360a to 200/200 Bastion and 400/400 THPS:HD