Banshees (Teen Wolf); magical, such as Kanima's neurotoxin
Isabel (A Fierce and Subtle Poison)
Zombines (Half-Life 2 Series)
The Courier (Fallout: New Vegas); via Heartless perk
Suu (Monster Musume)
The Toxin Suit (Unreal Series)
After three years of training with Orochimaru, Sasuke (Naruto) had developed resistance and immunities to many poisons.
After his encounter with Magellan, Luffy (One Piece) gained anti-bodies that make him immune to many poisonous substances.
With the power of the Doku Doku no Mi, Magellan (One Piece) is immune to all poisons, including his own.
The Flash Bees (My Little Pony: Friendship is Magic) are highly immune to swamp fever.
The Gasu Gasu no Mi made Caesar Clown (One Piece) immune to poisonous gases.
Vinsmoke Reiju (One Piece) has complete immunity to the deadliest venom that can kill Giants and even Luffy.
Bianchi (Reborn) is able to eat her own poisoned cooking without ill effect and believes the poison enhances her cooking.
Wolverine's Healing Factor protects him from poison, including the metallic poisoning from the Adamantium that is stored in his body.
Poison Ivy (DC Comics) is immune to all forms of poisons/toxins.
Sōsuke Aizen's (Bleach) tremendous regeneration powers gained from the Hogyoku allowed him to survive the deadly poison of the Kamishinino Yari.
Suu (Monster Musume) can consume any foods that could result food poisoning to both Humans and Extraspecies, and even discerning what's poisonous and what isn't. The only side effects being that she develops a more abrasive way of speaking after eating poison.
Most Zoldyck family members (Hunter X Hunter) are trained to resist all kinds of poison and electricity.