Marking the end then the beginning of a block of text?

Hi All,
Back in the Day (and maybe in the present for people who, unlike me, code) there was a way of marking the beginning and end of a block of text with brackets encircling letters such as [b] and [e]. I’m wondering if there’s a way to select text using this approach? For example, suppose I’m editing a piece of long form writing and find where I know a block of text has to end, but still need to muck around at the beginning of the block, is there a way I can mark it then once I have my beginning mark that and manipulate the new block of text? (One workaround is to mark the end with something like *** and then search for it after the beginning is in place, but I was hoping for something more streamlined.) I’d mainly use this in the writing app Scrivener, but I could imagine it being useful in any text editor.
Thanks!
-P