Background Bounce Sweep

A colored background wipes across the element from one edge on hover.

Add a "Background Sweep" hover effect (also called background fill or slide fill) to [where].
A new background color should wipe across from the left edge to the right, smooth and quick with no bounce, and retract the same way when the pointer leaves, while the label color switches to stay readable.
Keep the fill clipped inside the element's shape, and show the same effect on keyboard focus.

A rectangle expands or contracts inside the element to change its background on hover.

Add a "Rectangle Fill" hover effect to [where].
The new background color should close in from all four edges as an inner rectangle shrinks toward the center, and open back out when the pointer leaves, while the label color switches to stay readable: smooth and quick.
Keep the label above the fill, and show the same effect on keyboard focus.

The background opens or closes like shutters from the center or the edges on hover.

Add a "Shutter Fill" hover effect (also called shutter) to [where].
The new background color should open from a line down the center out to both sides like shutters, and close back to the center when the pointer leaves, while the label color switches to stay readable: smooth and quick.
Keep the fill clipped inside the element and the label above it, and show the same effect on keyboard focus.

The background and text color cross-fade to a new color on hover.

Add a "Background Fade" hover effect (also called color fade) to [where].
The background and text colors should cross-fade smoothly to new colors while the pointer is over the element, and fade back when it leaves: calm, with no movement.
Keep enough contrast between text and background in both states, and show the same effect on keyboard focus.

The element floats up then bobs or hangs up and down continuously while hovered.

Add a "Bob" hover effect (also called hang) to [where].
The element should float up a little, then keep bobbing gently up and down while the pointer stays over it, and drop back when the pointer leaves: slow and soft.
Loop the bobbing only while hovered, and keep it still for users who prefer reduced motion.