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