There are 3 main rarities for SoftBot traits: Normal, Special, and Exclusive.
ESSENTIALS
Important traits that make a SoftBot a SoftBot include:
- A singular straight horn on their forehead! Must be the same colour as the blood in the tubing and the eyes.
- A pair of furred ears!
- A furred tail!
- A drape over said tail!
- A furred body- with a mane, cat-pawed feet, and humanoid legs. Fur must reach all the way to the top of the neck and must have at least sparse markings.
- A single, blood-filled core double in size compared to the horn base diameter in the center of their chest, at least two blood tubes on the body symmetrically, and at least two tubes on the tail. Special tails that are long and slender, such as Long Flex, however, do not have to abide by the tubes on tail rule.
- A face that's got a human nose, and is a natural skintone.
- Metal rims around the tubing where it leads into the body.
Good VS Bad SoftBot Examples
Acceptable SoftBot
This SoftBot has all the essentials! Optionally, all SoftBots have 'kneepad' joints filled with blood, but you do not need to have them visible like this one does, and you also do not have to have extremely fluffy fur, it can be smoother!
Unacceptable SoftBot
This is surely not a SoftBot at all! It lacks the drape, furred body, non-furred humanoid face, horn, and pawed feet that SoftBots are known for! We also do not allow pawed hands or tubing on the head outside the single horn. All the tubing seems to have a different colour inside as well, which is not allowed either!
SoftBots also all have flat chests.
Additionally...
All SoftBots have humanoid legs! While we have accidentally accepted SoftBots with anthro-style legs in the past, we have discontinued this and it is now an illegal trait.
Though, with prosthetics (That are clearly robotic in nature, no workarounds!) a similar appearance is possible.
These are also just plain wrong.
SoftBots must also have healthy, normal skintones! Below are examples of the range a SoftBot's skin should be: 
Horns
All SoftBots have a single horn in the middle of their forehead! They're connected to their internal tubing system and are often small to prevent breakage. Humans gave them these due to their fascination with a mythical creature called a Unicorn. SoftBots like to decorate and notch it as a status symbol among other things! Ones with a cracked or broken horn are often pitied by their peers...
NOTE: Horns are part of their internal tubing system, so they must be the same colour as the blood!
Lengths
Small and Medium horns are Normal, while Long horns and Nub style horns are Exclusive!
NOTE: Horns cannot be curved unless the ailment Hylica Catalis is present!
Horn Decoration
Some SoftBots like to add decorations or notches to their horns.
These don't have rarity and can be freely added to any SoftBot! They often signify status or important life events, like marriage or a birth.
NOTE: Notches must be pronounced and should not give the appearance of a bendy, thin horn.
Horn and Core Sizing
When making a SoftBot, please keep in mind the size of the core in relation to the horn's base! Cores should always be either twice the size of the horn's base or larger. Think of the core as their heart! You wouldn't want your poor SoftBot to have an undersized heart... would you....?
Additionally, as long as it doesn't look like a nub horn, feel free to give your SoftBot a broken horn!
Ears
SoftBot ears come in many shapes and sizes! Typically, if it's a similar style to that of fluffy mammals from Earth, it is considered Normal!
Types outside this restriction, such as larger than normal ears or ones not seen on furred Earth mammals are considered Special, and fully mechanical ones are Exclusive. Human ears are a no-go, by the way!
Normal Ears
Any and all furred ears of mammals on Earth can be considered Normal! This goes for animals like rabbits, foxes, stoats, cats, deer... if you can prove an animal on Earth has it, you can use it!
To the left are examples of several different Normal ear types. From left to right, there are: Cat, Stoat, Wolf, Deer, and Rabbit.
Special Ears
Furred ears that are a bit unique and are not found on Earth mammals are considered Special! This goes for larger than normal ears as well- something can be an Earth mammal ear type, but if it's huge compared to the head of the SoftBot, it is Special.
To the right are examples of several different Special ear types. From left to right: Large Ribboned, Wings, Plume, Large Mouse, and Batty.
Exclusive Ears
Entirely unfurred, mechanical ears are seen as an oddity, and are Exclusive! Those that rock them are treated with reverence and awe.
To the left are examples of several different Exclusive ear types.
Tails and Drapes
The same restrictions that apply to the ears also applies to the tail!
However, Normal tail lengths must be equal to or less than 3/4ths of the SoftBot's height.
In addition, drapes are a must for any SoftBot! Normal drapes only have 1 layer and are made of fabric.
Two layers and non-fabric, organic materials such as leather are considered Special. 3 or more layers, as well as mechanical, and it's Exclusive!
Normal Tails and Drapes
Any and all furred tails of mammals on Earth can be considered Normal! This goes for animals like rabbit, fox, stoat, cat, deer... if you can prove an animal on Earth has it, you can use it! The only exception are limp hair-tails, like that of a horse's.
To the left are examples of several different Normal tail types. From left to right/top to bottom, there are: Fox, Cat, Lion, Shiba, and Rabbit/Deer.
Single layer drapes are shown as well. You may add things to them such as fur rims and scalloping, but it must be obvious these are attached to the ends.
Special Tails and Drapes
Furred and partially-furred tails that are a bit unique and are not found on Earth mammals are considered Special! This goes for longer than normal tails as well- something can be an Earth mammal tail type, but if it's huge compared to the body of the SoftBot, it is Special.
To the right are examples of several different Special tail types. From left to right: Spade, Long Flex, Fishy, Split, and Large Curl.
Two layer drapes are shown as well. As with the Normal drapes, you may add things like fur rims, scalloping, and the like to the edges of each layer.
Exclusive Tails and Drapes
Entirely unfurred, mechanical tails are seen as an oddity, and are Exclusive! Those that rock them are treated with reverence and awe, just like with those with mechanical ears. Even more so if the SoftBot has both at once!
To the left are examples of several different Exclusive tail types.
Metal drapes, tattered/torn drapes, as well as 3+ layer drapes also lie here.
Blood Colour
All SoftBots have blood coursing through their tubing! Think of it like the liquid found in liquid-cooled computers, except they need it to live.
The Normal colours are Red and Black.
Special blood colours are more vibrant...
while white and pastels are Exclusive.
This is the expanded list of what colours are what rarity.
Also, the metal rims around tubes can be any colour, not just gold or silver!
Fun Fact!
SoftBots are actually born without their tubing and need to have it surgically added or they die a quick and painful death. A special mineral harvested by the many shooting stars that hit Poltera every year is mixed with the fluid within, which determines a SoftBot's blood colour. This was done to keep SoftBots dependent on humanity, but they eventually perfected it for themselves.
Some aspects taken from HTML by @Eggy