Q:

Block entire sections of HTML in jade/pug instead of individual lines

In Jade/Pug you can render out raw HTML with pipe
| <div>some stuff</div>

Is there an effective way if you need to block out hundreds of lines?

A:

Yes, just use a period at the end of the parent tag.  This is used a lot with script elements:
script.
  (type as many Javascript lines as you want here)

Look under the header "Block in a Tag" in the Plain Text documentation

