Here is the full list of all 14 Creature Card Idle achievements.
Earn 1K gold in Intro Realm
Earn 100K gold in Intro Realm
Earn 10M gold in Intro Realm
Empower a Crab in Intro Realm
Have a sheep call a Meteor to the center of the earth
Buy 100,000 5-card packs in one go
Earn 25+ gold/sec with only Ghouls
Ascend, earning at least one gem, for the first time
Unlock the Haunted Woods expansion
Unlock the Underworld expansion
Earn +500 wood/sec with only Lil' Lumberjacks and Hatchets
Unlock the Plains of War expansion
In Plains of War, kill the Scarecrow in one hit
Kill a Dead Fish in 4 or more rounds