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