Here is the full list of all 13 ECON - there are Elemental Connection achievements.
Finish any competition with no mistakes by either player
Clear all Challenges
Win against a human opponent
Lose against a human opponent
Gain 20 points in a single placement
Beat the Creative AI
Beat the Simplistic AI
Beat the Normal AI
Beat the Mindful AI
Beat the Thoughtful AI
Clear 10 Challenges
Win a game without any misconnections
Beat the Efficient AI