The list:
Kindred
Red Goblin
Regent
Morlun
Solus
Kuhul Ajaw
The Spider Queen
(pre-retcon) Judas Traveller
Anti-Spider-Man Skrull (Secret Invasion)
Carnage
Venom
Sandman
Hydroman
The Extremist
With prep:
Alystair Smythe
Jackal
Mr. Negative
Given the right circumstances / special versions:
Norman Osborn (Super Adaptoid)
Hobgoblin (Word of God)
Electro (Anti Matter Version)
People Spider-Man fought on his own but are not actually "Spider-Man villains":
Firelord
Juggernaut
Dr. Doom
Mephisto
Thanos
Originally posted by carver9Kaine was The Other at that point, the Other is basically a person destined to be able to kill Inheritors. That's why Spider-Man was able to kill Morlun with his stingers. Kinda like what Drax was for Thanos during Annihilation.
You don't think Kaine could win? Didn't Kaine kill Solus
But you can add Sin-Eater (Kindred version)