Based on real world rats & rodents along with commonly associated critters and the occasional fantasy rat.
Sewer Rat
Fungal Rat
Maned Rat
Rot Rat
The Sewer Rat grew up in the harsh enviroments of New York sewers. Ew.
Sewage Swimmer: Growing up swimming in disgusting water, you're a great swimming that can hold your breath from much longer than most.
Dark Sewers: Having lived in low light conditions, you've adapted your senses to thrive in these conditions.
Trashy Diet: You eat just about anything you can find, including rotten foods.
Rat Poisons: With poisons changing so often you can't adapt to them, letting them severely hurt you more than normal.
Righting Reflexes: Twisting and turning in the air you can land mostly unscathed.
Night Scurrier: More active in the dead of night for safety from predators.
Snack Size: Your small ratty body is the perfect snack for cats, foxes and wolves.
Munchies: Your small raty body gets really hungry really fast.
Fungal Rats grew along the giant mushrooms on Mushroom Islands. Fungal rats carry mushroom spores on their backs and sometimes take boats made of mushroom caps across the seas to spread the spores.
Favorite Meal: Having grown up on an island with only mushrooms to eat, you have developed a taste only for fungus.
Spore Spreader: The spores in your fur fall out sometimes when running or jumping, causing a mushroom to sprout if it's dark.
Addicted: Going to long without eating a mushroom will cause will cause you to feel like your starving, even if you aren't hungery.
Exotic Cuisine: Eating Crimson or Warped Fungus gives you fire resistance and either haste or speed however they don't give saturation.
Predator Naivete: Due to there being no threats on your home island, you don't know how to defend yourself that great and have weaker claws. You also don't know how to use ranged weapons.
Bergmann's Rule: Thanks to the lack of predators and the plentiful food, your body shrunk to optimize for the tropical climate.
Hallucinogenic Fur: The spores in your fur are hallucinogenic to most so when you shake your fur creatures nearby may become nauseous.
Natural Predators: The natural predators of rats hunt you as well, cats, foxes, and dogs will all attack you.
Fungal Rat Poison: Unuse to poisons of the rest of the world, they are extremly potent against you.
Rats who grew up eating normally toxic plants now weaponize their toxicity, personal space is advised.
Toxic Glands: Releasing poisons through glands on your paws, when you activate your main ability hitting people with your power item will inflict a poison and Toxic Fur becomes stronger.
Toxic Fur: Due to your toxic eating habits, when somethings gets to close to you they might become poisoned.
Washed Clean: Being in water or out in the rain will wash away your toxic oils. It will take a while for your Toxic Fur to return.
Root Eater: You're a herbivore that also eats roots.[Crouch when holding Hanging Roots, Rooted Dirt or Mangrove Roots]
Maybe once a rat, now a grotesque beast of rotten flesh and sunken eyes.
Sensitive Skin: Being out in the sun without a hat will scorch your rotten skin.
Decaying Body: Due to the lack of life for poison to kill, your immune! However because your to far rotten, regeneration can't heal you.
Cravings: You hunger for flesh and meat, and only those. Flesh is extra satiating however you hunger faster.
Decaying Bite: Hitting something with your power star will inflict it with withering for a few seconds.
Apart of the Horde: The Udead recognize you as one of them and won't attack unless provoked, however Villagers run and Golems attack on sight.