After I posted my entire non-TCG Seviper collection yesterday, @bbobrob mentioned I was missing two variants I wasn’t even aware of, which I was luckily able to find right away and have now incoming. Thanks again for the heads up, Robert! 
3D version of the Top Seika Gum Zangoose vs Seviper card:
Patapata Sealdass Travel Map vol. 2 (Kanto):
EDIT: As well as a sealed Japanese Double Crisis Deck Box. Thanks @lyleberr.
Greetz,
Quuador