Some links:
Inkjet printable metallic and holographic adhesive film and paper. Not sure how reliable this place is for customer service. Super Pricey!
Super heavyweights (260gsm-300gsm) photo papers. Looks like the Metalic Sliver Lustre is out of stock-that is the one I use.
https://www.itsupplies.com/Metallic-Inkjet-Paper
Finally had issue printing on this one-ink pools on top, but if you can reverse/mirror print the back side works great:
Silver Foil Paper - 12 x 12 in 10 pt Cover | Paper Store 24/7 Mirror Finish Paper 3-WFP0051U
Another source: Looks like they went the way of the Dodo Bird...
Mike