Lucian, yi, and kat are the only 3 who do literally nothing 'supportive' at the kit level, but could still function as kill lanes that require snowballing. (Kat does technically provide grievous wounds on her ult.)
Theres many more whose only 'supportive' effects are on their ults, and many whose 'supportive' things are super inferior to alternatives (considering vayne a 'peel' support because of her condemn is pretty crap for example).
It's something I've put a reasonable amount of thought into as I've earned almost all of my S rank chests in the support role (with another half dozen or so from aram), and theres a lot of definitely not optimal, but it can work supports out there (e.g. sup ori can build like and play similar to a peeling shield bot), and particularly if you happen to be good at any given champ it can make up for their not so optimal support kits.
I'd say theres probably 50+ champs that someone could play in the support role and not feel like they're blatently trolling, but making a point to force every champ into the role will just feel bad. You could certainly do it since you'll inevitably eventually snowball or otherwise get carried just by random chance no matter what you're playing as long as you're not inting, but theres not much point to it, and you'd probably get a lot of flak from teammates when you're pushing the far side of off-meta.