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