Bastien Salabanzi's nollie heel back tail down a rail in Sorry and Erik Ellington's switch flip fs tailslide at UCI in This Is Skateboarding. They were both pretty small rails, but I can't think of many instances of anyone doing those tricks since those parts.
Chad Tim tim nollie heel front tailed the same rail bastien skated, which was way looked over as well, and unlike those other two tricks, Timtim's was perfectly done.
Jeremy Wray's entire career is overlooked. He 270 sugarcaned the hollywood high rail in The Revolution. Even with all of the weird smithy type tricks people have been doing lately it still hasn't been replicated. Ollie the SD sports arena triple set, utter destruction of Carlsbad...there was a lot.
Also, I'm assuming its due to his overall kookiness, but Josh Kasper fucking murdered Carlsbad, but nobody ever really talks about it anymore. I suppose the benihannas and kasperholics shit probably didn't help his legacy.