Only other example I can think of is Royston before electrification was extended to Cambridge, although there were a few through peak trains.
No there weren't - once electrification reached Royston, Cambridge lost its through services to Kings Cross until electrification and the only direct Cambridge to London services were via the West Anglia line to Liverpool Street.
There were a few peak hour trains between Kings Cross and the intermediate stations to Huntingdon until that got wired, but Cambridge lost out for 10 years until the wiring was extended.