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