Britain fielded many specialist wartime units

Were there British special forces besides the Commandos and SAS?

Yes - Britain used many, including the SBS, Chindits, Long Range Desert Group, MI9, SOE, and numerous smaller detachments.

British specialist forces included the Chindits, Long Range Desert Group, SBS, MI9 and SOE alongside the Commandos and SAS. Numerous small detachments performed other tasks. The later SBS incorporated several wartime groups, including an earlier organization bearing the SBS name.