Support is one of the harder roles to carry on but its not impossible. The two types of supports you should play in low elo are Poke or Engage, these types of champs are the easiest to carry on because they can function even with a weaker adc.
Poke- Generally these champions offer a lot of lane pressure through constantly chipping away at the opponents health. However they are also usually very squishy so positioning is very important. Champions like Sona, Zyra, and Karma are the standard when it comes to poke support champions. The reason why they are very strong in low elo is because players lack the ability to dodge poke and will often over extend or stay in lane too long and die. With these champs it is best to pressure hard and build some early health to survive an all in. After this you can transition to damage and truly carry your team through constantly poking.
Engage- These champions are usually built as tanks with hard cc and abilities to absorb a lot of damage. They are very strong at all in's due to their ability to lock down an opponent for a long amount of time. Examples would Leona, Braum, and Nautilus. If any of these champions can get on top of an enemy carry they can CC them as your team deals the damage. These champions are very strong at snowballing as they increasingly get tanky and are able to engage constantly to pressure and bully out opponents.
Other champions that can carry but are harder to play would be Annie, a squishy burst mage , and Thresh a high skill shot dependent engage champion.