Tanks don't count as supports (unless they have some kind of support ability).
Unless a tank has some kind of support ability, they should not be played as a support. The enemies can just ignore you and attack your adc, then focus you.
Examples of Tanks with support abilities:
Passive
Heal
Even frikkin
with his speed boost
Examples of Tanks without support abilities who are still played as support anyway:
where the hell is this guy coming from
throwback does NOT count as a support ability
its like people just give up on trying to get top lane and go support
Please stop. Having cc does not make someone a good support.
Mages who have legitimate support:
true sight
speed boost, shield
healing, sight, attack boost
??
Watch your mouth kid, or you'll find yourself respawning at home.
Why are these monsters viable supports
and you just need more damage.
TYPE B:

and
) but you end up asking yourself the same cc/damage questions.
class of tanks because with any type of lifesteal they become drain tanks with more effective hp than any tank