When you pre-order 1 box of S3 Infinity Zone at big retailers in Japan, you will recieve an exclusive card storage box & promo card pack as a bonus.
This promo pack includes special Infinity Zone logo stamped promo's of the upcoming Infinity Zone cards. These are Hoopa, Galarian Obstagoon, Eternatus V, Eternatus VMAX, and a Darkness Energy. Eternatus V and VMAX contain different artwork. These would probably release internationally as a Box or Tin promo.
From what it seems, you get 1 random promo out of 5 different promo's in the promo pack.
Update 29-5-2020: Added official images of the promo cards.
Thank you to kamui_kyoshiro