>>43283333buff Seviper so it heavily favors Sp. Def. Give it something like
>85 / 85 / 105 / 55 / 115 / 55Total of 500, which puts it on the tier as stuff like Houndoom, Scizor, Donphan, and Hawlucha, for example.
Buff Poison Tail to something like 100 BP and 70% Accuracy. Change its effect to work like Corrosion so it can inflict damage and Poison opposing Poison and Steel-types. It's a high power move with a good effect balance by low accuracy.
Since Seviper's stats favor Sp. Def now, it can run a mono attacking set of Coil/Rest/Poison Tail/Filler with a max HP/Sp. Def Careful spread. It already learns Glare and Dragon Tail so they can patch up the moveset. Rest + Shed Skin is a tale as old as time but you can run Sleep Talk instead with Infiltrator so you aren't stopped by Sub spamming,
Zangoose would get the same stats reorganized, so something like
>85 / 115 / 85 / 55 / 55 / 105Toxic Boost is buffed so it double's the user's attack if it is poisoned at least. Anything less than this just makes it a shitty version of Guts, which it already is. Possible additional buffs would be a bigger increase if the user is Toxc Poisoned and/or negation of Poison damage if he user actually is Poisoned. Probably not both because it would make Toxic Orb too OP.
Crush Claw becomes a Normal version of Darkest Lariat so it can break through Seviper's Coil spam. Or make it a Normal version of Leaf Blade. Something so it isn't just a worse Return.