Dude we need a lot more than this. We need EV's, Natures, Abilities, IV's (if they are changed for Hidden Power).
Now onto the problems at hand. First off, none of the plates are Viable except on 2 occasions: used on Arceus, or used on Scizor, and even then it's just Iron plate that should be used, not the Insect Plate. Scizor is not fast enough really to use Iron Head, and since you're using Bug Bite, I assume you're using Technician. Since you're running trick room on Slowking I also assume you want to run a Trick Room Team to make Rampardos blazing fast...that being said I suggest you make your entire team a Trick Room Team. I offer you this set:
Scizor @ Choice Band
EV's: 252 HP / 252 Atk / 4 SDef
IV's: 0 Spd
Brave Nature (+Atk, -Spd)
Bug Bite / U-Turn
That will get you a lot farther than using what you got. And with STAB Technician Choice Banded Bullet Punch coming off a base 130 attack....anything you attack will be in for a world of hurt. Your Ttar should be a DD set if it is planning on being offensive, Stealth Rocks if defensive. Take Outrage off and put Superpower, Pursuit for Crunch to trap, or leave it if you don't want a trapping TTar. Finally DD or Stealth rock in place of Protect. Yawn and Dream eater do NOT work well on Slowking, trust me on that. Dream Eater isn't too viable. and People will just switch out on the Yawn, I guarantee you you will put almost nothing too sleep. I don't run Slowking often but look up a good defensive set, that should do you some good.
I don't agree with saying Rampardos is unviable in OU; I've seen it rip through teams using Trick Room support, and if I of all people can make Kangaskhan somewhat Viable in OU, I'm sure someone can make Rampardos Viable. But this set is just terrible. It should have life orb and different moves. I'd give you a move set, but I never thought about using Rampardos before. Finally, your Porygon z is completely unviable. You're lacking a good special wall unless you use special wall TTar. I would switch this to Bulky Eviolite attacking Porygon 2. Here is the set I use:
Porygon2 @ Eviolite
EV's: 252 SAtk / 252 HP / 4 Def
IV's: 0 Spd
Quiet Nature (+SAtk, -Spd)
This set gives you a second trick room set up while also giving you some fantastic bolt/beam coverage that will hit almost everything at least for neutral damage. Anyway that's all I can really think of. I hope some of that info helps you somehow.