which iRules reference this pool

No problem. Since rules are just stored as text internally and processed at runtime there are now ways to speed up the lookup aside from searching through the text of a rule and searching for the given pool name.

What makes things a bit more compilcated is when you are using variables for pool names

when HTTP_REQUEST {
  set pool_to_use "pool1"
  if { [HTTP::uri] ends_with "foo"} {
    pool $pool_to_use
  }

Customers are doing this when they want to create a pool of pools and dynamically assign connections to that pool based on some external criteria (incoming ip, portion of uri, etc).

Since this isn't your case, then doing a string search for the string "pool pool1" should work (as long as you don't add extra spaces in between "pool" and "pool1".

This looks like a great contribution to CodeShare! If you supply it I'd even be inclined to get it in an upcoming SDK!

-Joe