Kamalisk
Missing 98001 and 98004
These pages show prompt “your query didn't match any card“: https://arkhamdb.com/card/98001 https://arkhamdb.com/card/98004
Yeah, these are the alt-art investigators, which we have marked as 'hidden' since they don't contain any new text/deckbuilding info, just different art.
They have a different back_flavor. UPD: Also, by the same logic, Carolyn should be hidden, too, but she's present.
once we solve the "duplicate" problem, the hidden cards can be made viewable, until then they are hidden so we dont get into a mess. Caroyln is special because she was a book investigator first, so her appearance in a proper set is hidden instead.
I have an idea (it may be obvious, but I'll spill it all the same)
Cards get a new attribute, "duplicate". Its value is a card code of the original card. Duplicates are shown in pack listings, one can see them when addressed directly or through prev/next buttons. FAQ sections, errata, reviews and comments are inherited from the original. For everything related to deckbuilding, a non-null "duplicate" attribute is effectively the same as "hidden":"true".
It looks like arkhamdb needs this kind of thing for a ton of duplicates introduced in the investigator decks.