Here is the full list of all 38 World of Warships: Legends achievements worth 1,000 gamerscore.
Simultaneously have 5 American or British commanders in your roster
Simultaneously have 5 Japanese or German commanders in your roster
Capture a key area or base 3 times in Standard battles
Destroy enemy ship modules 100 times in Standard battles
Score 5 citadel hits in a single Standard battle
Earn 20 ribbons (excluding the 'Target Hit' ribbons) in a single Standard battle
Promote Commander to legendary rank 1
Win a Standard battle while being the sole survivor in your team
Destroy 20 enemy ships in Standard battles
Set enemy ships on fire 7 times in a single Standard battle
Destroy an enemy ship dealing 50% or more damage with a single salvo in a Standard battle
Research a Tier V ship
Research a Tier III ship
Promote a Commander to rank 7
Defend the base or a key area 3 times in Standard battles
Own 10 Japanese or German ships in any proportion at the same time
Promote a Commander to rank 2
Install a ship upgrade
Win a Standard battle and survive while also obtaining the highest XP of your team
Win a Standard battle and survive while part of a Division
Survive and win any battle
Play 100 Standard battles as a Destroyer
Play 100 Standard battles as a Cruiser
Play 100 Standard battles as a Battleship
Destroy 200 enemy ships in Standard battles
Destroy 50 enemy ships with your torpedoes in Standard battles
Destroy more enemy ships than any other member of your team (at least 5) in a Standard battle
Win a Standard battle and survive while also earning 200,000 credits
Destroy at least 4 enemy ships in a single Standard battle with an American or British ship
Destroy at least 4 enemy ships in a single Standard battle with a Japanese or German ship
Destroy an enemy by fire that exceeds 50% of its HP in a Standard battle
Destroy an enemy by flooding that exceeds 50% of its HP in a Standard battle
Install 6 upgrades or modifications in any combination on a single ship
Unlock and install all modifications on a Tier VII American or British ship
Unlock and install all modifications on a Tier VII Japanese or German ship
Own 10 American or British ships in any proportion at the same time
Promote a Commander to rank 11
Promote a Commander to rank 16