How do I use vim registers?

Question

I only know of one instance using registers is via CtrlR* whereby I paste text from a clipboard.

What are other uses of registers?

Answer 1

From vim's help page:

CTRL-R {0-9a-z"%#:-=.}                  *c_CTRL-R* *c_*
        Insert the contents of a numbered or named register.  Between
        typing CTRL-R and the second character '"' will be displayed
        <...snip...>
        Special registers:
            '"' the unnamed register, containing the text of
                the last delete or yank
            '%' the current file name
            '#' the alternate file name
            '*' the clipboard contents (X11: primary selection)
            '+' the clipboard contents
            '/' the last search pattern
            ':' the last command-line
            '-' the last small (less than a line) delete
            '.' the last inserted text
                            *c_CTRL-R_=*
            '=' the expression register: you are prompted to
                enter an expression (see |expression|)
                (doesn't work at the expression prompt; some
                things such as changing the buffer or current
                window are not allowed to avoid side effects)
                When the result is a |List| the items are used
                as lines.  They can have line breaks inside
                too.
                When the result is a Float it's automatically
                converted to a String.
        See |registers| about registers.  {not in Vi}
        <...snip...>