Here is the full list of all 67 Crystal Maidens achievements.
Lose 500 battles
Upgrade 30 legendary items to the level 5
Find 10 legendary items in the Campaign Mode
Upgrade a building up to level 10
Find 5 legendary items in the Campaign Mode
Upgrade 10 legendary items to the level 5"
Play 500 battles with Engineer class
Play 500 battles with Marksman class
Upgrade 1 legendary item to the level 5
Upgrade 30 epic items to the level 5
Lose 100 battles
Upgrade 10 epic items to the level 5
Upgrade 1 epic item to the level 5
Upgrade 30 rare items to the level 5
Find a legendary item in the Campaign Mode
Upgrade 10 rare items to the level 5
Upgrade a skill to the level 20
Play 500 battles with Support class
Play 100 battles with Engineer class
Play 100 battles with Marksman class
Romance 15 maidens to level 3
Play 15 days in a row
Play 50 battles with Engineer class
Play 50 battles with Marksman class
Lose 50 battles
Play 500 battles with Mage class
Earn 1 million coins in Campaign Mode
Upgrade 30 common items to the level 5
Get a hero up to level 60
Upgrade 10 common items to the level 5
Play 100 battles with Warrior class
Earn 250.000 coins in Campaign Mode
Play 7 days in a row
Earn 180 stars in Campaign 1
Romance 5 maidens to level 3
Kill 1000 enemies in battle
Upgrade 1 common item to the level 5
Play 100 battles with Support class
Complete level 60 of Campaign Mode
Win 50 battles with all 3 stars
Upgrade a building up to level 5
Play 100 battles with Mage class
Upgrade 1 rare item to the level 5
Get a hero up to level 30
Earn 120 stars in Campaign 1
Play 50 battles with Support class
Own 10 maidens
Own 15 maidens
Own 5 maidens
Play 50 battles with Mage class
Kill 250 enemies in battle
Upgrade a skill to the level 5
Complete level 30 of Campaign Mode
Win 20 battles with all 3 stars
Earn 60 stars in Campaign 1
Play 50 battles with Warrior class
Kill 100 enemies in battle
Upgrade a building up to level 2
Earn 5000 coins in Campaign Mode
Romance 2 maidens to level 3
Get a hero up to level 10
Win 5 battles with all 3 stars
Complete 50 quests
Complete 200 quests
Complete 10 quests
Complete level 1 of Campaign Mode