Here is the full list of all 12 Ageless achievements.
Complete the Game
Finish Exodus
Collect All Relics
Finish Spectre
Finish Vestige
Collect 60 Relics
Talk to everyone in Remnant Village and Vestige Tribe.
Finish Remnant
Collect 30 Relics
Talk to everyone in Remnant Village.
Stay underwater for one minute straight.
Finish Pandora