Meteors

Thin glowing lines travel along paths, sometimes exploding when they hit a surface.

Add a "Background Beams" effect (also called light beams or background lines) to [where].
Faint curved paths should sit in the background while short glowing streaks travel along them one after another, at a calm, steady pace.
Stagger the beams so they never move in lockstep, keep them behind the content, and stop them for users who prefer reduced motion.

Tiny stars twinkle or drift across a dark space-like backdrop.

Add a "Starfield" background (also called a stars background or twinkling stars) to [where].
Tiny stars of different sizes should twinkle softly at their own pace while the whole field drifts very slowly: quiet and calm.
Keep the number of stars modest so it stays light, and stop the twinkling and drift for users who prefer reduced motion.

A fine speckled texture overlays the page, sometimes flickering like film grain.

Add a "Noise / Grain Texture" overlay (also called film grain or a noise background) to [where].
A fine, faint speckled texture should sit over the surface and flicker in small jumps like film grain: subtle, never strong enough to muddy the content.
Let clicks pass through the overlay, generate the texture once instead of every frame, and keep it still for users who prefer reduced motion.

Many small dots drift, connect or react to the pointer across the background.

Add a "Particles" background (also called floating particles or a particle field) to [where].
Small dots of different sizes should float and drift slowly in gentle, wandering paths, each at its own pace: calm and airy.
Keep the number of dots modest so it stays light on slower devices, pause it when it is off screen, and stop it for users who prefer reduced motion.

Blur strength ramps gradually toward an edge so content fades out softly.

Add a "Progressive Blur" edge (also called a gradient blur edge) to [where].
Content scrolling toward the edge should get gradually blurrier and softer, ramping smoothly instead of cutting off at a hard line.
Show the blur only at an edge that still has more content beyond it, and keep the blurred area from blocking clicks or scrolling.