Pulse Placeholder

Gray placeholder shapes show a light highlight sweeping across them.

Add a "Skeleton Shimmer" (also called a skeleton wave or shimmer effect) to [where].
A soft band of light should sweep across the gray placeholder shapes from left to right and pause briefly before the next pass: smooth and unhurried.
Match the placeholder shapes to the real layout so nothing jumps when the content loads, and show static placeholders to users who prefer reduced motion.

The element gently scales or fades in and out repeatedly.

Add a "Pulse" effect (also called pulsing) to [where].
The element should gently swell and ease back in a slow, steady rhythm: subtle, with no bounce.
Loop it seamlessly without shifting the surrounding layout, and stop it for users who prefer reduced motion.

A tiny blurred version of an image sits in place and sharpens as the full image loads.

Add a "Blur-Up Placeholder" image loading effect (also called LQIP or a blur placeholder) to [where].
A tiny, heavily blurred version of the image should fill the image's space right away, and once the full image has loaded it should sharpen into place smoothly and fairly quickly.
Reserve the image's exact size so nothing shifts when it arrives, and clip the blurred edges so they do not bleed past the frame.

A thin bar at the top of the page creeps forward during navigation and finishes on load.

Add a "Top Loading Bar" (also called a page progress bar) to [where].
A thin bar along the top edge should dart forward at first and then creep more and more slowly while the page loads; when loading finishes it should race to the end and fade out.
Never let it reach the end before loading is actually done, and keep it from covering or shifting the page content.

Three dots in a bubble pulse or rise in turn to show someone or an AI is composing.

Add a "Typing Indicator" (also called typing dots) to [where].
Dots inside a small chat bubble should rise and brighten one after another in a soft, gentle rhythm while the other side is composing.
Keep the loop seamless, remove the bubble as soon as the message arrives, and give screen readers a short status text instead of the dots.