Loaders

Something is happening and its end is not known. Both of these say that much and refuse to say more — where the end is known, the bar on the next tab says it instead.

Spinner

A machine is busy. Three sizes, and an inline alignment for when it stands in a line of text rather than in a box of its own.

Processing data

Dots

Something is about to be said. The same three sizes, and the same alignments — what changes is who the reader is waiting for.

The other side is writing

Vue

Both ship as vue partials too, taking the same options, for a page that decides while it runs whether there is anything to wait for.