From the front cover:
This additional druid spellbook contains all of the circle spells a druid might gain from the lands they call home.
From the back cover:
Contains 21 durable, laminated cards for Druids from any Circle of the land. The perfect supplement to complete any Druid's collection of spells.
These cards are included in Spellbook Cards: Druid (Version 3) in the same format as the rest of the Spellbook Cards sets released in 2017.