Sulfur: Looks a bit like Spongy. Despite looking like two characters who are enemies, he and Phosphorus are actually best friends. Chlorine: Sodium's best friend who looks like CH from LHDA. Argon: A bystander due to being unreactive. Potassium: A banana attached to its peel. Calcium: A skeleton of someone who got killed by Oganesson in the flashback. Its name is represented by it being hit. Scandium: A guy with a Viking hat due to being named after Scandinavia. Titanium: A guy with a sword. Vanadium: Equivalent of my Greek Ϡ. Chromium: A guy with a paint bucket. Manganese: A guy who can say his name in any language due to ending with -ese. Iron: Two twins who are the leaders of the heroes. Eventually they get killed and Silicon takes over. Cobalt: The same as my German Ö but doesn't own a gem. Nickel: The triplet sister of Copper and Zinc. Copper: The triplet brother of Nickel and Zinc. Zinc: The third triplet along with Nickel and Copper. Yes, they're non-binary.
Credit to everyone, especially @PhonicLover44 for the vectors, @AlfabetonsOfficial for the base of Chlorine, @LogoFan2016 for the base of Cobalt's glasses, and Mike Salcedo for Alphabet Lore.