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