Vettel at Monza this year (with the guy on the radio screaming “Stop the car!!” at him) – didn’t they drop out to avoid an engine-change penalty?
Damon Hill, in one of his last races for Jordan in 1999 – possibly the very last one in Japan.
Nigel Mansell, 1995, Imola (I think), parked his McLaren which was (all together now, in your best Brummie whine) “undriveable”.
Nelson Piquet, 1985, Portugal – the Pirelli wet tyres were hopeless, so he gave up.
I’m sure there was another wet race where Prost stopped, but can’t remember when.