There are a few of the really old Black and white episoodes before Joe Gannon joined and the series changed to color. its really pretty gritty with writing that was probably shocking back then. But there is a reason the series lasted over 10 years. It was just good television!
Dragnet
https://archive.org/details/DragnetTheBigFraud
https://archive.org/details/DragnetTheBigWill
https://archive.org/details/DragnetTheBigBetty
https://archive.org/details/DragnetTheBigLease
https://archive.org/details/DragnetTheBigPresent
https://archive.org/details/DragnetTheBigHate
https://archive.org/details/DragnetDragnetTheBigHands
https://archive.org/details/DragnetTheHumanBomb
https://archive.org/details/DragnetTheBigDance
https://archive.org/details/DragnetTheBigMother
https://archive.org/details/DragnetTheBigActor
https://archive.org/details/Dragnet-TheBigTrunk1954
https://archive.org/details/DragnetTheBigWinchester
https://archive.org/details/Dragnet-TheBigDeal1956
https://archive.org/details/DragnetTheBigPresent
https://archive.org/details/DragnetTheBigLamp
https://archive.org/details/DragnetTheBigChildren
https://archive.org/details/DragnetTheBigWar
https://archive.org/details/DragnetTheBigNewYear
https://archive.org/details/521218AGunForChristmas
https://archive.org/details/Lbines-DragnetTheBigShoplift596
https://archive.org/details/DragnetTheBigHitRunKiller
https://archive.org/details/DragnetTheBigPhoneCall
https://archive.org/details/Dragnet_The_Big_Girl
https://archive.org/details/Dragnet_TheBigCrime
https://archive.org/details/Dragnet_S05E12_-_The_Big_Bounce