A group of sloths has no commonly used collective term.
Although some enthusiasts appear to prefer a “snuggle” of sloths.
Also, a “bed” of sloths is becoming popular among fans of sloths.
The irony is that Sloths tend to be solitary animals, so a collective noun associated with them seems absurd.
Animal classification words are not officially created by any organisation.
The thing with collective nouns is, if people use them often enough, then they kind of become official in everyday language.
Collective nouns (the words used to describe gatherings of things, particularly people and animals) are a fascinating part of the English language.
Many of the collective nouns that are still in use today were invented in 15th-century England, when naming game animals was a popular activity. A group of crows is called a “murder”, while a group of owls is called a “parliament”.