Are the rest of the C&D decks in the color expansions, or the artifex deck?
Artifex-Deck are the remaining A cards.
The 2018 release will have a name starting with B and have the remaining B cards.
C-Deck will be 2019, some of those cards are in the Wizkids Mini decks.
D-Deck will be 2020, some of those cards are in the Wizkids Mini decks.
All those 4 decks will have cards for 1-4 players.
All cards from A-D for 5/6 players are in the 5/6 player expansion.