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