From Nookipedia, the Animal Crossing wiki
Gyroids (埴輪, Haniwa) are furniture items in the Animal Crossing series, primarily used as furniture inside the player's house. They are not to be confused with the gyroid that appears outside the house in Animal Crossing. They can be found buried in the ground, like fossils, but only after rainy days.
Each and every gyroid is unique in its own way: the way it sounds, how fast the tempo is, and pitch all depend on the size of the gyroid and which family it belongs to. If one of K.K. Slider's songs is played on a stereo, the gyroid will match the tempo of the song so that they synchronize. The name "gyroid" likely originates from the word "gyrate," meaning to spin, referencing the motion that gyroids make.
In Animal Crossing: New Leaf, more gyroids appear buried in the ground after it rains for a long time. Lazy villagers comment on this saying that they must like the rain.
Eight gyroids may be active at one time in a room before one of them automatically turns off, although in Wild World, only four may be active at any given time.
Note: Not all gyroid families have all the sizes of gyroids, and a few do not have a neutral size. There are 127 gyroids in Animal Crossing, Animal Crossing: Wild World and Animal Crossing: City Folk. In Animal Crossing: New Leaf, there are 131 gyroids.
These gyroids make a sound similar to a steel drum.
These gyroids make a mooing noise, hence the "Bovoid" name.
Bowtoids wear bow ties. They make a fast, repetitive sound and dance.
Buzzoids make a buzzing noise.
They sound like pots and pans banging. They appear to look like garbage cans.
They croak like a frog.
These gyroids sound a little bit like they are saying "Dekkai."
These gyroids, as their name suggests, make bell sounds. The Wee Dingloid is the only "Wee" gyroid and is very similar to the Mini Dingloid.
The Dinkoids are a lot like Sputnoids.
These make a drilling noise.
The Droploid makes a "plop, plop, plop" sound, like water falling.
They make an echoing noise.
These sound like the fizz of opening a pop bottle.
These sound like crying babies.
These make a sound like a man gargling water.
The Harmonoids make a sound like a Steam Calliope.
Howloids make a screeching noise like an owl.
Lamentoids are based off of the word "lament," and make rattling sounds when they spin. They do not have the same facial features as most gyroids do.
These make a metalic rattling sound.
Nebuloids sound like a vibrating beep.
Oboids sound like an oboe.
The Oombloids make an "oom" sound.
Percoloids sound like hitting a hollow tree trunk.
They sound like tiny wooden bells.
These make a scary shriek.
These gyroids sound like a person blowing on a pan flute.
These make futuristic-sounding noises.
They are in tune with the music.
These make a clanking noise, like rusted metal.
Sproids make a noise similar to that of a spring.
Their names derive from the satellite Sputnik and make the noise of a spacecraft drifting through space. These Gyroids have metallic bodies and large, colorful panels.
They sound like Velcro.
These Gyroids make sounds similar to a guitar. The name comes from the strum, a basic guitar technique.
Timpanoids sound like timpani drums.
Tootoids make a noise that sounds like flatulence.
Warbloids make a sound like a woman gargling water.