Another plugin option is NrrwRgn, which has editing benefits as well.
I’ve seen people use a trick to flash cursorline and cursor column as well, as a sort of "where am I." This is not hard to do, but I’ll see if I can find the exact code later.
limelight.vim works great for fading paragraphs of text. I don't know if it works for code blocks also. It can still be a good starting point to look up the fading functionality, since getting current cursor line in vimscript is trivial, with functions line() / winline().