Here is the full list of all 27 Ooblets achievements.
Sell 100 crafted items
Sell 50 crafted items
Fulfill 15 Plenny's orders
Scan 25 ooblets at the Lernery
Travel to Tippy Top
Craft 20 items
Travel to Pantsabear Hill
Collect 40 things from the sea dangler
Complete 20 Tinstle Tasks
Collect forageables from 4 different regions
Travel to Port Forward
Scan 10 ooblets at the Lernery
Win 3 dance barn tournaments
Get 10 friendship stickers
Harvest 50 crops
Complete 10 Tinstle Tasks
Win 15 dance battles
Travel to Nullwhere
Get 3 friendship stickers
Travel to Mamoonia
Scan 3 ooblets at the Lernery
Win 5 dance battles
Complete 5 Tinstle Tasks
Look at 10 thingiedoodles
Get 150 friendship points
Plant 15 seeds
Collect 60 forageables