19:58 Brighton-Victoria. 12 car 387, empty until Gatwick, 10 minute connection at Clapham for my train home. And fast too, only 4 stops.
Similarly, 17:42 Brighton-Littlehampton. Fast after Worthing and you could really get some speed out of a 313 if the driver was hungry.
More unusually, when the Waterloo works were on and there was a fast train from Staines to Clapham every 15 minutes!
Another that's sprung to mind are the 1654, 1754 and 1854 Waterloo-Farnham via Hounslow (though I think the 1654 still runs). They were less than 5 minutes slower but also empty because all the people using Reading trains for a fast train to Richmond or Twickenham couldn't use this one, and (presumably) a not insignificant number of people would see "via Hounslow" and assume it was the all stations train.