I've had a few PMs about this, so I'm just going to reply here and clarify my earlier post.

I personally don't have a list of carriers that lack interline YQ tax agreements, however, if I did it wouldn't really matter since it is not common for airline sites to allow you to purchase tickets on their website that don't involve either a flight on them, or their alliance partner(s).

However, if you were to go to their ticket desk, any prices they quote you would not include the YQ.

The only other one that comes to mind is 9W at the moment.

But like I said, it doesn't matter since you can't book anything but 9W on their site.

All that said, you all are welcome to try each of IATA's 230 member airlines to see (a) which have websites, (b) who allow bookings on other airlines, and (c) don't collect YQs.