The apostrophe key is also very useful, to jump quickly to a particular link.

Unfortunately a lot of websites have no searchable text on their links. Sometimes the problem is that it's an icon; other times the problem is that the text is not added in a way that allows search (I don't HTML enough to know all the ways). This is in addition to all the clickable elements that aren't tabbable, ugh.

I've also found a significant number of scrolling/sliding and menu-like elements where tabbing does weird things (partial scroll, not adjacent, etc.).