Here is the full list of all 35 Time on Frog Island achievements.
Complete the game within 5 (in-game) days
Throw 1000 items
Leave the island in your fixed boat
Stay airborne for 7.5 seconds
Complete every quest and fully build your house
Complete all of The Cartographer's quests
Replace your broken rudder with a new one
Grow every bounce mushroom on the island
Find and complete the hidden time trial
Knock over all of the carefully stacked stones in a day
Complete the frog statue ritual
Proudly display a honeycomb in your house
Pay The Carpenter to build all three stages of your house
Duplicate a coin by farming it
Speak to every frog on the island
Purchase something from the merchants shop
Throw an item then grab it with your tongue before it hits the ground
Replace your broken wheel with a new one
Sleep in every camp
Replace your ripped sail with a new one
Take your pet plant up the mountain to see the northern lights
Take your pet plant to see all the sights
Take your pet plant to the western island to see the Dodos
Take your pet plant to the western island to see the ruins
Take your pet plant into the town to see the frogs
Jump 1000 times.
Take your pet plant to the eastern island to see the strange ruin
Replace your torn rope with a new one
Complete the tavern questline before accepting any boat pieces
Catch your first fish
Brew your first potion
Evaluate the damage from the storm
Obtain the Ice Herb before opening the mountain door
Walk 10km
Ask a frog about the same item 3 times in a row