I'm a big fan of the SnapLock storage boxes by Hugo and remixed handy card game boxes by mteomarch, however I couldn't find a design I liked for my playing cards.  After printing a plain box without anything on top I later decided to design this topper and glue it on which I must say I'm super pleased with.

The card prints face down.  I use a Bambu Lab A1 mini without an AMS and use manual filament changes to achieve multi colour print. 

Card dimensions 60mm x 90mm x 0.6mm