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