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