Here is the full list of all 18 Mindset achievements.
Complete six packs
Complete four packs
Complete two packs
Finish ten random levels
Complete a hard random level
Complete all levels
Find two hundred hard sets
Find fifty very easy sets
Find one hundred fifty medium sets
Find one hundred easy sets
Complete fifty levels
Complete twenty-five levels
Use every symbol in the game at least once
Find a hard set first on a board
Find a hard set
Complete ten levels
Find any set
Finish Training