Hey all,
Reports of missing cards after the patch are likely due to the “Standard Shake-Up” event ending. 23 cards in total were moved from Standard back to Wild with the most recent patch (16.0). You can read more about the Standard Shake-Up and what cards were included here: Hearthstone Update – October 8 – Doom in the Tomb!
One of our Community Managers also created a forum post to warn palyers ahead of time in the Multiplayer Discussion forum.
What this means is that if you had the cards in Wild prior to October 8th (when the Standard Shake-Up event started) you will keep those cards in your Wild collection. However if you did not obtain the cards from packs or crafting previously, then they would have been granted for free temporarily only for the duration of the event.
Hopefully this clears things up!