#! funniest home videos with bob sag it
#2 rescuer 911
#3 Unsolved mysteries

Personally, I think Reality shows started long before those.

To name a few.....
The Original Amateur Hour (1948)
Candid Camera (1948)
The Dating Game (1965) Even though it was a Game show of sorts it was also Reality.
Real People and That's Incredible in 1979 and 1980

#! funniest home videos with bob sag it
#2 rescuer 911
#3 Unsolved mysteries
Rescue 911 and Unsolved Mysteries were more like dramatizations of actual events and AFV was just funny videos submitted by people, I don't think any of those shows presented on the spot shocking events.

Its been say that COPS is the one that started it all.