Yinglets
Based on http://www.valsalia.com/chapter/the-val-salian-regional-field-guide/ and http://www.valsalia.com/comic/out-of-placers/the-val-salian-regional-field-guide-entry-7-yinglets-revealed-part-22/ . Second link is Part 2 of the last entry in the first one that for some reason is not included.
Racial Information
Yinglets are small, furry, bipedal creatures with long, stilt-like forearms and forelegs, large eyes and ears, two whiskers poking out of the inner edge of each eyebrow, often possessing actual "hair" as well, a long, fur-covered tail, like an otter, and a "shell-tooth", a large, chissel-like tooth in the center of their snouts used for prying open mollusks, or as a last-ditch weapon. Their short fingers have one less section / joint than human fingers and end in a short claw with a bulbous pad to assist in gripping. Their bones are mostly hollow, almost avian in design, despite having no capability of flight. Transparent irises, reptile-like pupils as well.
They have a minor speech impediment due to tooth structure, rendering them unable to make the "th" sound, and thus must replace it with a suitable substitute, such as instead of saying "The others are headed for that town down the road." they might say "Za ozhers are headed for zat town down za road" or the like. This does not impact verbal spell components, usually.
The average Yinglet member seen outside of enclaves is a bit...dim, with the rough intelligence and emotional maturity of an adolescent human. As they are often seen as nuisances and 'vermin', they often lack proper education, though they are quite capable of learning. As they are a relatively young species with little coin, property, or education, having only appeared in the world at large little over a century and a half ago, many are employed with simple tasks such as relaying messages or small items or keeping an eye out for thieves in markets, though they may also be "adopted" into a household as housekeepers, general servants, or even simply for companionship like a pet. It is reported that many actually enjoy being "kept" by humans, though this is a matter of heated argument within the Yinglet community.
The vast majority of Yinglets, 80% of their species, are males, and males are usually the ones outside the enclave as the females are kept under guard as leaders. Usually the only case of a Yinglet female being outside of an enclave is when one is sent to establish a new enclave, a survivor from a destroyed one, or in rare cases, a human magically transformed into one through various means. Due to this wild gender imbalance, males are generally expected to find companionship with other males, as the female leadership will generally only pick the most "beneficial" males to continue the species, whether that be a particular skill, being stronger than average, more capable of learning, etc.
Yinglets often gather into small 'towns' called Enclaves, with one Matriarch at the head who grooms the females for leadership duty. Below her are the Patriarchs, who each govern an area of speciality based on their expertise. A Patriarch of Coin and Trade for example negotiates trade with other enclaves and with the region as a whole, while a Patriarch of Foodstuffs handles cooking, farming, and some hunting not already handled by the Patriarch of Scouting and Intel's hunting parties, and a Patriarch of Culture might handle written records and recording the enclave's history and notable figures. Below them are "specialists", each assigned to a Patriarch. So that Foodstuffs has cooks, haulers, storage managers and such, Culture might have scribes, Scouting has hunting parties and spies, and so on.
Yinglets, barring a proper mutation, are unable to eat grain-based foods, such as bread or rice, which block them up and make them ill, so the yinglet body has adapted by causing near instant vomiting upon ingestion, however they are capable of enjoying almost every other food that humans can, and even some they might not, such as their absolute love for raw clams, oysters....or slugs. In fact, their 'shell tooth' evolved specifically to pry open clams first and as a weapon second, and their tongue has bristles at the end that are made to latch onto clam-flesh and pull it loose in one lightning-fast motion, like a chemeleon tongue, and eating "slime-flesh" such as those causes an intense rush of dopamine and endorphins like a drug. Gorging on them can render them bubbly and giddy, as though drunk or on heroin without the crash, jitters, or many side effects, along with a lack of drug resistance.
Rumors abound of a famed Yinglet alchemist who created "Healthy Juice" a potion that extended his lifespan immensely by slowing the aging process to a stop, or nearly so...before he was eaten by a stray dog and the formula promptly lost until it is rediscovered once again.
Male Yinglets come in two varieties: Receptive / Preening and Aggressive / Seeking, based on their temperament and minor biological differences.
Preening Yinglets tend to be those males with feminine features such as rounder ears and shorter snout, shorter shell-tooth, thicker fur including longer hair-like fur on the top of the head and a significant tuft of hair at the end of the tail. They tend to decorate their tails with adornments such as bells and rings in the hopes of attracting Seeker types, and typically have a more social attitude and tend to spend more time at Enclaves as nurses, diplomats, or scholars.
Seeking Yinglets are those with traits generally considered more masculine: Longer limbs, thicker forerams and forelegs, long shelltooth. They typically have an "aggressive" attitude, though note that "aggressive" does not mean "hostile" and is meant that they are simply more 'active' than their receptive / preening counterparts, usually preferring physical pursuits to intellectual ones. Often accompanied by a desire to range far from the enclave to hunt, scavenge, and adventure, and otherwise generally having a high level of confidence and self-assurance.
Racial Attributes
Yinglets are highly variable and prone to mutation, and as such, their ability scores are subject to that variance as well. Your Ability Scores may have an additional 3 points distributed among them, but you may not have more than a +2 in one stat, such as +2 Dexterity and +1 Intelligence. Usually Preening Yinglets go for mental, and Seeking go for physical, but this is not a hard and fast rule.
Your size is Small. Your height is an average of 3 feet. Yinglets can be anywhere from 2 to 4 feet tall, but most of them are 3 feet and average around 40 pounds.
Your Speed is 25 feet and you may:
Hyperactive Sprint: While Yinglets are capable of incredible speed when they need to, they exhaust their energy quickly. On your turn you may double your speed for that turn. After use you cannot do so again until you spend a turn 'resting', and moving 0. See Feline Agility for the Tabaxi race in Volo's Guide to Monsters
Lifespan: Yinglets are considered adults by age 2 and old age by 40, though magic and alchemy can extend this greatly.
Shell Tooth: Yinglets may bite with their shelltooth like a dagger for 1d4 + strength or dexterity. In a pinch this tooth may also be used as a tool to pry open small objects, such as a rusted-shut locket or a clam, adding a proficiency bonus to requisite rolls to do so should they be required. In addition, they may take the Sickly Spit racial feat to boost this attack, seen below.
Power Naps: Yinglets do not sleep through the night like most creatures. Instead they nap in 1 hour intervals every 4-5 hours. If they have slept a total of 5 hours through these naps over the course of 24 hours, they count as having had a Long Rest at the end of the final nap. They can stay awake for longer, but each nap cycle missed counts as sleep deprivation until they are able to nap again.
Spring-loaded Arms: Yinglets' arms are adapted to and prefer thrusting weapons due to their ancient history in the marshes of their homeland snatching fish out of the water. (Proficiency: Rapier, lance, pike, trident)
Gross Gourmand: Evolving in a marsh / swampland full of poisonous plants has given them a resistance to poison damage, as well as having advantage for resisting poisons.
Special Saliva: Yinglet saliva has antibiotic and mild painkilling properties. If a Yinglet has not recently ingested toxic substances and is allowed to lick a wound on themselves or another, it gives advantage to resist the wound becoming infected and removes penalties due to pain from that wound for three hours. The time it takes to complete this depends on the severity of the wound, with minor wounds taking mere moments and larger wounds potentially taking a few minutes. Many "bootleg" healing potions in their home region include Yinglet saliva as a filler for this reason.
Ferrets on Stilts: Because of their long, skinny legs adapted to wading through water and dealing with the soft, wet sand of the shore, they ignore rough terrain through mud, wet sand, high water, and similar conditions to marshes and shorelines.
Prehensile Feet: Yinglet feet can function as hands, though rarely useful due to the fact they obviously can't walk while holding something or doing anything with them and are always counted as off-hands.
Racial Feats
Sickly Spit If the Yinglet has ingested a poison that they have successfully resisted, they may transfer that poison through their saliva into their bite attack made within the next 2 hours. On the bright side it lets you retaliate against a poisoner with their own toxin. On the down side you have most likely been stabbed...
Optional Flavor: Mutations:
Yinglets are highly prone to mutations and oddities, from the below examples, or may make your own. As a general rule of thumb they should be flavorful and not impact the game mechanically, being meant to give ideas for interesting quirks and roleplay. You are not limited to just one, obviously, but please keep in mind common sense when trying to pick between two effects that may conflict.
Unusual Fur: You have bright and colorful fur or it is in an unusual style, this may be a mishmash of colors or an unnatural color such as blue. This can be full-body or it may be restricted to head-fur, like a large green afro.
Furless Forearms: Your forearms resemble your legs, being either short haired or hairless. A very common mutation.
Fluffy Legs: Your legs are furry like (most) yinglet forearms. Enjoy the extra preening!
Fluffy Tail: Like a female Yinglet, if male, you have a large fluffy tuft of fur at the end of your tail almost as large as your head. If female, the tuft is especially large and fluffy.
Fluffy Everything!: Your fur is unusually luxurious and fluffy, often combining Fluffy legs and Fluffy Tail, but that is not required.
Two Toozh! You have two front teeth like that of a rodent. Useful when one falls out or cracks before they regrow!
The Odd One "Snout": Your snout is unusually long, or short and rounded.
Duckfoot: Your feet and fingers are webbed!
W(ear)d: Your ears are incredibly large, almost bigger than your head! Alternatively, or in addition, they may be pointed and long, or short and rounded.
Go See A Dentist: Your shelltooth is sharp and jagged, resembling a poorly-sharpened dagger.
Tall!...For a Yinglet: You have almost an extra foot in height over your fellows, rendering you 4 feet tall, though you still count as Small. This could be because you have much longer legs, really living up to the "furballs on stilts" stereotype, or your legs may be thicker and stockier with your height coming from just plain being bigger than average with the thicker legs to handle the extra bulk.
I Didn't Know They Could Get That Small!: You're short, even for a yinglet, averaging around 2 feet tall instead of 3 feet, though you still count as small. Usually because of very short, yet stocky and wide legs rather than the long and thin legs of their normal counterparts.
Eye See You: Unlike most yinglets you have visible irises instead of the normal transparent ones! One of the most common mutations and quite harmless. They are often a color that contrasts and sticks out from the main eye, for example orange-eyed yinglets having reddish irises.
Heads or...Tail!: Your tail is unusually long, extending a distance almost equal to your height.
Bread and Circuses...What's a Circus?: Unlike most Yinglets, you have a beneficial mutation that allows you to eat grain products like wheat, rye, or rice. Go you!
Lovely Liver: Your liver has decided to extend its normal toxin resistance to alcohol as well. It does it so well in fact you can't be rendered drunk nor will you suffer negative effects from booze! Shame if you enjoy being drunk though...