In addition to those that were converted to Metro, there was also the Riverside line which closed in 1973.Then there are the Tyneside 3rd rail electrics that became diesel worked before conversion to Tyne and Wear Metro.
Woodside - Addiscombe, 1997
Dover Western Docks about 1992 I think
Haywards Heath - Horsted Keynes 1965 I believe
Nunhead - Crystal Palace High Level, 19 fifty something.
Folkestone Jnc - Folkestone Harbour - a couple of years ago.
Bury to Holcombe Brook reverted to steam for its last year or so, because the electrification equipment was worn out, but not worth repairing / replacing. Passenger services ceased in May 1952.Bury to Holcombe Brook
Haywards Heath to Horsted Keynes