Hmm, Okay let me see.
Hulk the raging green turtle head against symbiotes. Of course I'm biased towards the Symbiotes, but I'm not complitely idiot. (D'oh)
Venom and Carnage are somewhat equal in the terms of strength. (Both max at 70 tons) Toxin.. Hmm, I'm not so sure about him. He's propably at a same level than his father and granpa. (Because he's rather young at the moment, but he gets stronger under pressure)
Symbiotes can withstand helluva physhical trauma. Punches and stuff. They also regenerate quite fast.
Hulk.. Hulk's a green vegetable.. Though a vegetable with huge ass sterngth and durability. He starts from 80 tons which is more than the Symbiotes have, and his strength grows from it.
Now, I doubt his healing will work if he's under constant attack (Maybe I'm wrong?) Venom's claws, Carnage's axes/ shitz and Toxin's claws are sharp enough to penetrate Hulkster's skin, but I doubt they could inflict enough damage, before Hulk reacts.
C'mon, I know he's like smart as my dog. (Sorry doggie), but still I doubt he would let them attack him without doing anything.
The symbiotes can hardly win by banging his head all day long, because Hulk's strength grows all the time. So he'd eventually win.
It depends how well the Symbiotes play together. If they can somehow distract Hulk and stuck their tendrills in his ears/nose/mouth/ass/weeweeplace they could destroy his brain or turn him into a vegetable.. Oopsie, but he's already one.
I'd give this for the Green man 7/3 (I doubt the Symbiotes will play it together, so that's why so low score)
PS. Dont take my comments on Hulk so seriously. I know he's a special boy and needs lub. 😄