Here is the full list of all 26 Lightyear Frontier achievements.
Feed 50 animals.
Increase Homestead Coziness to 3.
Explore the vault in Outset Grasslands.
Build the radio tower.
Restore all regions in Outset Grasslands.
Remove 150 Noxious Slimes.
Plant 1000 seeds.
Increase Homestead Coziness to 2.
Plant 500 seeds.
Feed 20 animals.
Remove 700 Noxious Weeds.
Get 10 upgrades at the Upgrade Depot.
Explore 7 ruins.
Remove 300 Noxious Weeds.
Plant 100 seeds.
Spray water at another player.
Remove 100 Noxious Weeds.
Increase Homestead Coziness to 1.
Explore a ruin.
Remove 50 Noxious Slimes.
Get an upgrade at the Upgrade Depot.
Scare away 10 animals.
Restore a region.
Remove 10 Noxious Slimes.
Feed an animal for the first time.
Plant your first seed.