Is there even such thing at this point? I was just interested where I can see scans of the cards yet to be released and are speculated for next set. It's ok, you can judge me about looking too far ahead.
PokeGym does not catalog Japanese cards, IIRC. I'd post a relevant site, but seeing as I help maintain bits of said site, I cannot per rules.
As for speculation, we're probably getting the rest of Black and White Collection and Beginning Set in BW2, with some Red Collection mixed in. Would list what cards these are, but then I'd be obligated to source.