Here is the full list of all 22 Plunder Panic achievements.
Kill an Enemy in Any Match Type
Make the Winning Action
Complete the Tutorial
Win via Rowboat 3 Times
Win via Plunder 3 Times
Win via Cannon 3 Times
Win via Captain 3 Times
Get 1 of Each Victory Type
Win a Conquest Match
Win a Rival Crew Match
Get 100 Kills
Get Swatted Away by Swabby 20 Times
Win as Captain 10 Times
Win as Crewmate 10 Times
Get Killed by a Kraken 5 Times
Equip a Captain's Hat 10 Times
Defeat an Enemy Crew of 6 AI
Play 50 Matches of Any Type
Win a Rival Crew Series Undefeated (Best of 5 or Greater)
Win a Conquest Series Undefeated (Best of 3 or Greater)
Increase Your Bounty to 25,000 Gold
Complete the Campaign