I got curious about this so I looked it up on the ol' Ngram Viewer. Went through a "list of unusual animal group names". In some cases the unusual name was literally never used, in some cases it had once been used but is falling out of favor, in some cases there was maybe one person who used it in writing a century ago and then more recently people dug it up and brought it back, and in some cases it's a complete neologism, never having been used before the late 20th century.

I attribute some of these trends, especially the spike in the more exotic names since the early 2000s, to the ability to check online for something. In regular speech I think people revert to the simpler categories of pack, herd, flock, school, swarm, cluster.