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