NAT X7 Traws Hafren Bristol - Chepstow/Magor serves Bristol, South Gloucestershire and Monmouthshire.
First Cymru X10 Swansea - Sarn for Cardiff serves Swansea, Neath Port Talbot and Bridgend.
T6 Swansea - Brecon. Swansea, Neath Port Talbot and Powys.
The T1C had a mention earlier with 1974 counties. It now serves Ceredigion, Carmarthenshire, Swansea*, Neath Port Talbot, Bridgend and Cardiff.
*The M4 Junction 44 Bowens Arms stop is between the Swansea and Neath Port Talbot County Boundary signs just outside Skewen.
In 1996 I travelled from Cardiff on the longer predecessor to the T1C. The Traws Cambria 701 Porth - Holyhead which served 10 local authorities. Rhondda Cynon Taff, Cardiff, Bridgend, Neath Port Talbot, Swansea, Carmarthenshire, Ceredigion, Powys, Gwynedd, Isle of Anglesey.
My timetable is dated 1995 when it would have been 6 or 7. Mid Glamorgan, South Glamorgan, Mid Glamorgan again, West Glamorgan, Dyfed, Powys, Gwynedd.