Determinate Progress Bar

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.

A bar or ring fills as the user scrolls through the page or article.

Add a "Scroll Progress Indicator" (also called a reading progress bar) to [where].
A thin bar along the top should fill from left to right in step with how far the reader has scrolled, reaching full width at the end.
Tie it directly to the scroll position with no easing lag, and keep it from covering the content.

A bar segment sweeps repeatedly along a track when the duration is unknown.

Add an "Indeterminate Linear Progress" bar (also called an indeterminate progress bar) to [where].
A short segment should sweep along the track from one end to the other again and again, quick and smooth, while the length of the task is unknown.
Let the segment enter and leave the track completely so the loop has no visible seam, and mark it as a busy progress bar for screen readers.

A circular arc grows around a ring to show percentage complete.

Add a "Progress Ring" (also called circular progress or radial progress) to [where].
Starting at the top, an arc should grow clockwise around the ring to show the percentage complete, easing out as it settles, while the number in the center counts up alongside it.
Keep the arc and the number in sync, and expose the value with proper progress bar semantics for screen readers.

A list of steps highlights or checks off one by one as a long task advances.

Add a "Multi-Step Loader" (also called a step loader or checklist loader) to [where].
The steps should light up one at a time from top to bottom, and each should get a small checkmark that pops in as it completes, at a calm, readable pace.
Advance the steps with the real task progress rather than a fixed timer, and announce each completed step to screen readers.