Topps Vampirella error card help

[NYnecromancer]

Hey there everyone. I have been trying to find info on the rarity of this card I have. I purchased this card in 1995 at a show. It is horror glow #6. It has no printing on the reverse side. I recently found the card, thinking it was lost, inside an encyclopedia. It is mint and has never been outside of the plastic. I am thinking of putting it on eBay but wondered how many more might be out there or if mine was the only one. I would greatly appreciate any information on the card's rarity. Or I could entertain offers from any collector. I have contacted Robin from Vampilore and he has a few scans I sent him an he will put them on his website soon. Thanks for all your help.

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