Animated CSS backgrounds and patterns to copy

Full-screen backgrounds that move: mesh gradient, aurora borealis, breathing gradient, liquid sunset, a dot grid in a wave, synthwave, a hexagon honeycomb, diagonal lines with light, a 3D starfield, a constellation, snow with depth, fireflies, film grain, moiré, brushed metal, water caustics, gooey blobs, coloured smoke, a lava lamp, Matrix rain, a CRT screen, a printed circuit, a radar, an audio spectrum, floating petals, drops on a pond, light rays and marble.

Use them behind a hero section, a login screen or a 404 page. Tune colours, density and speed live, then copy the code.