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