I don't know of a definitive list, but two that spring to mind (ex London) are Moscow and Kuwait.

Of course, there are also a number of short tag-ons like AUH-MCT, BAH-DOH and possibly some in the Caribbean that still have an F cabin.

>> I would presume the majority of long haul routes

Not so, Many longhaul routes are 3-class only, especially the leisure-oriented ones, and some previously longhaul routes are now narrow-body 2-class "midhaul"

Out of interest, why do you ask ?

hth