Nymph is also a word used to describe some kinds of baby bugs that look like mini versions of adult ones. Ah, how cute—okay, maybe not. (Source.)
The nymph form of some bugs that start their lives in water, like dragonflies, are sometimes called naiads after the water nymphs. (Source.)
A super heroine from the X-Men comic books was named Dryad, after the tree nymphs. Her mutant power was the ability to communicate with plants and to make them grow mega fast.
The moons of Neptune are named after watery beings from Greek and Roman mythology—including the moons Nereid and Naiad. (Source.)
In the DC Comics universe, Naiad is the Earth's water elemental, who's determined to destroy an oil company for polluting the ocean.