What are the different ways to visually hide content (and make it available only for screen readers)?

These techniques are related to accessibility (a11y).

• visibility: hidden. However the element is still in the flow of the page, and still takes up space.
• width: 0; height: 0. Make the element not take up any space on the screen at all, resulting in not showing it.
• position; absolute; left: -99999px. Position it outside of the screen.
• text-indent: -9999px. This only works on text within the block elements.
• .sr-only class for Bootstrap