Considering that other players may have unlocked more ducks than you have, it may be quicker to unlock any remaining achievements by joining a multiplayer room with other players.

The only limitation is that Quacking the Ice and Hippospace Download achievements are not available to unlock this way, considering that Infinity Cool is currently the only available map.

Three is company
Get a third rubber duck

Get the third duck.

Private pool
The slide is cool, I am cooler

Infinity Cool. Have a duck go down the slide to the smaller pool.

High-rise
Going up to the top with the elevator

Infinity Cool. Have a duck go up the elevator (pipe).

Make a wish
What else could I possibly want?

Watch a shooting star go by.

Catch a flight
No ticket needed, I'm not going anywhere

Watch a plane fly by.

Family pond (Hidden)
Just me and the ducklings

Wait for baby ducks to randomly spawn around momma (the base duck).

Cruise ship
A fun thing I'll never do again

Infinity Cool. Watch a cruise ship go by in the distance.

Ducks adrift
Around the world

Infinity Cool. Watch a flock of ducks float by in the distance.

Way to the shore (Hidden)
Gone exploring, I'll be right back

Have a duck escape into the distance.

Duck invasion
Get a twentieth rubber duck

Get the twentieth duck.

On fire
I'm a torch but life goes on

Have a flammable duck be burnt by any means (colliding with another burning duck, be burnt by incoming flames).

Abducktion
Aliens abducted me, I'll send a postcard

Infinity Cool. Have a cow duck be abducted by alien ducks.

Watery help
The fire is under control

Have a duck that's up in flames be extinguished by a duck that shoots a stream of water.

That's all, ducks!
Get all the ducks, enjoy life

Get all ducks from the base collection.

Floatpiercer (Hidden)
Go to sleep with the fishes

Infinity Cool. Have the pink flamingo move towards (or into) the pool from the storm/wind and get pierced by a duck with any sharp objects or parts.

Putting challenge (Hidden)
Ball is in: Pool

Infinity Cool. Spectate any duck that sinks to the bottom of the pool, you will find a golf ball just below the spawn point.

Magnetic feel
You make me feel like I am whole again

Have two opposing magnet ducks connect together.

Firequackers
Celebrate good times

Have the firecracker (firework) duck launch into the sky and explode.

Beeline
I just want to be around you

Have the flower duck bloom after rain/snow, then wait for the bee duck to come close and fly (float) around it.


None.

Quacking the ice
Enough floating, let’s skate

Have any duck go down the slide into the frozen hockey pond.

Fun-fun-funicular
Up we go again

Have any duck go up the funicular and splash back into the pool.

Hot tub
How warm and cozy up here

Have a burning duck light up the fireplace in the pool.

Off-piste ski (Hidden)
Back at the lodge with my friends

Have the woodpecker peck the frozen duck off of the tree branch.

Scoring challenge (Hidden)
Puck is in: Goal

While scoring the goal requires no action from the player, reportedly the achievement only unlocks if the camera is in proximity of the puck.

Campfire simulator (Hidden)
I like playing in the outer wilds

When a propeller hat duck flies out into the distance, use the binoculars to observe it at a campfire on a distant mountain.

Sailin' on
So I'm sailing, yeah, I'm sailing on

Have the ship in a bottle duck be destroyed by an exploding minion from the toy duck and have the ship set free.

Paranormal activity (Hidden)
What does a scanner see?

While in cyborg duck's view, scan a ghost duck floating by. Note that the required action is to switch to cyborg duck's view, the achievement otherwise plays by itself.

Hide and Seek
I'm the keeper of the secret art

Find all ninja duck's hiding spots, in any order, at least once (on either map, not both), by clicking on it.

Initial instructions are courtesy of John Travoltage.

Milk Away
Successful experiment

Have the UFOs drop five cow ducks into the cow-patterned funnel and watch as an "experiment" is done.

0 gravity
Never felt so light

Have a duck sink to the bottom right after it's released, entering the red teleporter, teleporting into the gravity-free flask.

Willy in orbit (Hidden)
Our friend's heading home

Have any duck reach the teleporter inside the large dome area, which releases the astronaut duck.

Pchooooooo!
Is that all it does?

Launch a duck using the duck launcher robot.

Initial instructions are courtesy of Skro.

Project BFD
Unlock the big jelly

Have the red, green and blue jelly ducks collide with each other and merge into a big white jelly duck.

It's mining crypto!
Get the miner to 100%

Get the crypto duck progress bar to 100%. It is necessary to spectate the duck for the progress to go up.

Play the game
You finally control a duck

Have the thief duck steal a coin from the piggy bank duck and place it onto the arcade cabinet duck, then interact with the arcade cabinet duck to insert the coin and play the game.

Annoying parrot (Hidden)
Listen to all the phrases

Quack the parrot duck and have it make all 12 unique sounds (4 of them learned by default). New sounds unlock every 10 minutes and the progress isn't saved when exiting the game or leaving to main menu. It's sufficient to leave the duck floating for 1:20h, then quacking it a couple of times.

Sounds (some are in Italian, bold: default):

1. Ah no-no (?)
   
2. (Confused grunt) Aaa-ooh?
   
3. Bella bah-ts (?)
   
4. Bah-goo-vill-yo (?)
   
5. Yip-yip (?) pappagallo (parrot) (?)
   
6. Auw!
   
7. Coo!
   
8. Nuh-uh!
   
9. (Lower pitch) Nuh-uh!
   
10. Nocto (night)
    
11. Hey, what's the problem? (?)
    
12. Bah-tah para-zero (?)

There is a, presumably, unused property "soundDetectionRadius" of value 15.0 that may indicate that the sounds were meant to be learned by listening to the environment, but proximity to ducks and other sound sources made no difference from testing.

Behind a tree


On the structure, above the safe door


Behind the beach ball


Under the chair


Under the slide


On the sand patch

Screenshots are courtesy of the original author.

On the fireplace

On the snowman

By the sign

Inside the small circular table

In the birch tree