Nice, thanks! I do spot one of the two Sevipers in that second image (bottom-center sheet of the nine, and then on the second row). 
So Yochien Mini Menkos it is. 
I guess that unpeeled sheet goes to my wanted list as well, haha. (And looks like there’s an item where Seviper and Grimer/Muk are sitting snuggly side-by-side, @joponnes. 
)
I do something similar, although only for things I know contains a Seviper, or items I’m unsure of whether it contains a Seviper. It sounds like you save even more pictures of every type of non-TCG item. Then again, there are likely a lot more items containing a popular gen 1 Pokémon like Mewtwo compared to an unpopular gen 3 Pokémon like Seviper.
(One example of pictures I’ve saved when I wasn’t sure whether Seviper would be among them are the Nikko black-and-white dias, for which I’m trying to compile a list of the four sets I’m currently aware of. Here are all pictures I’ve saved of those thus far, if curious.)
Greetz,
Quuador