Since most of the time I gander at insects, I am obviously biased toward Lepidoptera. Also, technically all insects fall under the Kingdom Animalia, so the inclusion of insects in the title is somewhat of a pleonasm. But to get back to the original question, I like what I call the “eye-outline” morph in Biston betularia and all of its associated subspecies. The funny thing is I had no idea that this feature even existed on the Peppered Moth until it was conspicuous on a specimen in North America.
The original observation https://www.inaturalist.org/observations/63008871 by @cyrusli.
Another majestic example of Insect coloration would be Attacus atlas ryukyuensis (if the genomic data still supports this designation). This insect is probably the closest thing to a real life Mothra (unless someone decides to inject it with radiation).
Original website: http://blog.livedoor.jp/lucanus/archives/52089106.html. (This is not my own picture)