Here is the full list of all 13 Pine Seekers achievements.
Win one Game
Draw one Game
100 Butterflies in inventory
500 Butterflies collected in one Match
Highest Butterfly Buff level
Ten crafted Pines
20 Pinecones in Inventory
Strongest Pinecone reached
Eliminate fast two players
Eliminate fast three players
Eliminate fast more than 3 players
Revive a friendly Skunk
Play a Match with 8 Players