Here is the full list of all 38 Minion Masters achievements. It takes around 200 hours to unlock all of the achievements on Windows.
Win a Ranked battle with 8 different Masters
Complete 10 Daily Quests
Win 100 Ranked Battles
Win a Ranked Battle with less than 100 Health left
Acquire a collection of 100 cards
Use 25 Power Tokens
Win 50 Ranked Battles
Play 5 spells in a row during a Ranked Match and then win
Complete 15 Achievements
Watch a replay
Craft a Rare card
Create 3 decks
Craft a Common card
Win against 8 different Masters
Reach the Silver League
Reach the Bronze League
Complete 3 Daily Quests
Win 10 Ranked Battles
Complete 5 Achievements
Reach the Stone League
Win 3 Ranked Battles
Acquire a collection of 50 cards
Complete 5 solo challenges
Complete 10 solo challenges
Complete 30 Achievements
Play a friendly challenge with 3 different friends.
Use 20 Resource Tokens
Use 50 Resource Tokens
Use 100 Resource Tokens
Use 100 Power Tokens
Use 250 Power Tokens
Craft a Supreme card
Craft a Legendary card
Win 500 Ranked Battles
Acquire a collection of 150 cards
Complete 25 Daily Quests
Complete 50 Daily Quests
Complete 100 Daily Quests