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