Allocated but unused airfield VHF frequencies ?
Do we still have any of these in the UK ? I don't know but I would be surprised if we did, given the pressure on the VHF airband. I remember East Midlands once had GMC as 121.9 but it wasn't in use in the early 1990s. More recently, Bristol had a GMC frequency but it was seldom used. Leeds Bradford has a Delivery frequency which is manned most of the time (Tower assistant job) but that doesn't stop KLM crews frequently trying to get their clearance from Tower and being patiently redirected.