Skew

The element turns by a few degrees when hovered.

Add a "Rotate" hover effect to [where].
The element should turn slightly clockwise while the pointer is over it and turn back when it leaves: smooth and subtle.
Keep the surrounding layout from shifting, and show the same effect on keyboard focus.

The element skews back and forth with decaying amplitude like a wobbling jelly.

Add a "Jello" attention effect (also called jelly) to [where].
The element should skew back and forth like a wobbling jelly, strong at first and quickly settling to rest.
Play it once when triggered, and keep the element's footprint so nearby content does not shift.

The element shoots in from the side with a skew that straightens as it lands.

Add a "Light Speed In" entrance animation (also called lightspeed in) to [where].
The element should shoot in fast from the side, slanted as if moving at speed, then overcorrect the slant once and straighten as it lands: fast and dramatic, slowing at the end.
Keep it from causing a horizontal scrollbar while it is still off-screen, and show it in place without motion when the user prefers reduced motion (prefers-reduced-motion).

A small speech-bubble triangle appears on one side of the element on hover.

Add a "Speech Bubble" hover effect (also called bubble) to [where].
A small triangle tail should slide out from behind one side of the element, turning it into a speech-bubble shape, and slide back in when the pointer leaves: quick and smooth.
Keep the tail the same color as the element so they read as one shape, and show the same effect on keyboard focus.

An inner border line appears inside the element edge on hover.

Add a "Trim" hover effect to [where].
A thin line should fade in just inside the element's edge while the pointer is over it, and fade out when it leaves: subtle, with no movement.
Keep the line inside the element so its size doesn't change, and show the same effect on keyboard focus.

A line slides in from the bottom or top edge into place to underline or overline the element.

Add an "Underline Reveal" hover effect (also called overline reveal or reveal) to [where].
A full-width line should slide up into place from just below the bottom edge while the pointer is over the element, and slide back down out of view when it leaves: quick and smooth.
Clip the line at the edge so it appears by sliding rather than fading or growing, and show the same effect on keyboard focus.