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