Here is the full list of all 29 Second Extinction achievements.
Kill 6666 Enemies.
Complete 40 Contracts.
Unlock all perks for one weapon.
Respawn 100 times.
Deploy 100 times.
Respawn 40 times.
Respawn 20 times.
Kill a T-Rex with a Supply Drop.
Play 20 missions at night.
Complete the mission "Contact".
Complete all core missions.
Complete the mission ”Black Site".
Complete 20 Contracts.
Kill 2000 Enemies.
Complete the mission "Homebound".
Deploy 50 times.
Complete a mission without using a Health Stim.
Kill 20 Enemies with Supply Drops.
Find the golden egg.
Deploy 20 times.
Complete 10 Contracts.
Deploy 10 times.
Kill 750 Enemies.
Complete the mission ”Research And Rescue".
Complete the mission "Vestige".
Complete the mission "Charged Extraction".
Complete a mission without any on the team having to respawn.
Take a raptor with you when you extract.
First Deployment.