Eh, another player who thinks he knows best, just because he knows meta. Meta is good to learn basics, but to play efficiently you need versatility and adaptability.
You might think support should buy sightstone, but players rarely escort them. They might get jumped and won't even have time to place a ward. As such, less tanky supports should go for blue warding trinket and use it as often as possible, to ward places in advance from safe distance,
You might think support should buy Redemption, but the core elements of this item are HP+mana regen and increased heal and shield power. Thus this item is best on 1) mana using tanks, to give them additional means of aiding allies on top of survivability (HP) and means to be helpful (mana) and 2) supports which excel at shielding and healing.
You might think support should buy Locket of Iron Solari, but its focus on mr and armor makes it pretty bad choice for any support that doesn't already have lots of HP from other items.
So you might now think: just play supports that can use them. Support is supposed to support and that means filling blanks in team composition. AD mid, top and jg with not much cc? Go for AP mage with CC like Veigar or Lux. Lack of tanky top and jg? Go for tank, like Braum. No AP and tank? Tank that can deal significant magic dmg then, like Vlad or Maokai. AP on every lane? Go for another AD carry, like AD MF or Ashe, so enemies need to split their focus between you and ADC.