People will tell you to go Electrocute and a full AD assassin build, but in reality, it's probably not the best overall.
Atm, I'm generally running:
Aftershock
Bone Plating
Conditioning (Since Pyke scaling AD doesn't have much armor, it's best to get extra where you can; otherwise he pops like a grape)
And Overgrowth.
My Secondary runes change with the game.
I generally get a
even though he's an AD scaler because I don't want him to melt. And it does wonders, even though his base AD isn't that great for sheen procs. Or
.
I generally avoid
because it doesn't give enough AD
The reason is..... there comes a point.... post about level 11 or so.... where Pyke just scales HP horribly vs damage outputs. He has a nice, practical CC and damage kit..... but if he has nothing to soak damage, the second he lands that "oh so perfect 4 man E stun," ....... boop. He's dead before they even get stunned.
If you want to maximize the use of his Passive, you need to have some tankiness, or he usually won't ever get out of the skirmish to abuse it. And it's worth sacrificing "some" of the front loaded damage to accomplish, because after he heals you can come back and harass opponents again.
If you don't build any tank and go Electrocute, you're likely to just be a "sit back and not actually use my champ" player except when someone's low enough to assassinate with R.