Por si só, o tipo gosma não tem (quase) nenhum impacto direto

Praticamente não há características ou talentos de raça / classe (ou feitiços ou itens mágicos) que se apliquem especificamente a gosmas.

Apenas dois feitiços, raio de Sol e reluzente, especifique:

Undead and oozes have disadvantage on this saving throw.

O tipo de criatura ooze também pode ser escolhido por um ranger como um Inimigo Favorecido, mas monstros / NPCs geralmente não são criados como os personagens dos jogadores, então isso não é realmente uma preocupação.

Se a corrida jogável tiver ambos os tipos humanóide e gosma, e assumimos que as coisas que se aplicam aos humanóides ainda se aplicam a elas, então quase nada realmente muda com base nisso.

... Mas pode haver outras implicações

O Monster Manual seção sobre gosma (p. 240) declara:

Oozes thrive in the dark, shunning areas of bright light and extreme temperatures. They flow through the damp underground, feeding on any creature or object that can be dissolved, slinking along the ground, dripping from walls and ceilings, spreading across the edges of underground pools, and squeezing through cracks. The first warning an adventurer receives of an ooze’s presence is often the searing pain of its acidic touch.

Oozes are drawn to movement and warmth. Organic material nourishes them, and when prey is scarce they feed on grime, fungus, and offal. Veteran explorers know that an immaculately clean passageway is a likely sign that an ooze lairs nearby.

Então, ao invés de apenas comer alimentos "normais", eles podem subsistir nos restos de basicamente qualquer material orgânico.

Ele continua:

Slow Death. An ooze kills its prey slowly. Some varieties, such as black puddings and gelatinous cubes, engulf creatures to prevent escape. The only upside of this torturous death is that a victim’s comrades can come to the rescue before it is too late.

Since not every ooze digests every type of substance, some have coins, metal gear, bones, and other debris suspended within their quivering bodies. A slain ooze can be a rich source of treasure for its killers.

A capacidade de absorver basicamente qualquer coisa em seu corpo, envolvendo-a, pode ser um pouco forte demais, embora só se aplique a criaturas de seu tamanho ou menor. Ainda assim, potencialmente uma capacidade dominada nos níveis iniciais.

Unwitting Servants. Although an ooze lacks the intelligence to ally itself with other creatures, others that understand an ooze’s need to feed might lure it into a location where it can be of use to them. Clever monsters keep oozes around to defend passageways or consume refuse. Likewise, an ooze can be enticed into a pit trap, where its captors feed it often enough to prevent it from coming after them. Crafty creatures place torches and flaming braziers in strategic areas to dissuade an ooze from leaving a particular tunnel or room.

Freqüentemente, as gosmas não são muito inteligentes. Isso poderia simplesmente se manifestar como uma penalidade racial na pontuação de alguém, embora não seja necessariamente verdade para todos os gosmas (os oblexos de Tomo dos inimigos de Mordenkainen são particularmente inteligentes, especialmente os Elder Oblex com sua pontuação Int de 22).

Spawn of Juiblex. According to the Demonomicon of Iggwilv and other sources, oozes are scattered fragments or offspring of the demon lord Juiblex. Whether this is true or not, the Faceless Lord is one of the few beings that can control oozes and imbue them with a modicum of intelligence. Most of the time, oozes have no sense of tactics or self-preservation. They are direct and predictable, attacking and eating without cunning. Under the control of Juiblex, they exhibit glimmers of sentience and malevolent intent.

Esta pode realmente ser a principal preocupação - muitas vezes se pensa que as lamas estão ligadas ao caótico demônio do mal Juiblex. (A outra principal preocupação é que o líquido é geralmente considerado estranho e estranho, por isso pode ser complicado conseguir que um humanóide confie neles ou trabalhe com eles ...)

Ooze Nature. An ooze doesn’t require sleep.

Gosmas geralmente não precisam dormir. É o mais fácil de se trabalhar, pois existem outras raças jogáveis ​​que não precisam dormir (os elfos podem tomar um transe de uma hora 4, e os forjados não precisam dormir). Essa característica também parece ser menos essencial ao sabor de uma corrida de gosma.

Também vale a pena olhar para o Slithering Tracker, o único lodo em Guia de Monstros de Volo (p. 191):

The quest for revenge sometimes leads one to undergo a ritual whereby they transform into a body of semiliquid sentience known as a slithering tracker. Innocuous and insidious at the same time, a tracker flows into places where a normal creature can’t go and brings its own brand of watery death down upon its quarry.

Vengeance at Any Cost. The ritual for creating a slithering tracker is known to hags, liches, and priests who worship gods of vengeance. It can only be performed on a willing creature that hungers for revenge. The ritual sucks all the moisture from the person’s body, killing it. Yet the mind lives on in the puddle of liquid that issues forth from the remains, and so too does the subject’s insatiable need for retribution.

Stealthy Assassins. A slithering tracker tastes the ground it courses over, seeking any trace of its prey. To kill, a slithering tracker rises up and enshrouds a creature, attempting to drown the prey while also draining it of blood. A slithering tracker that has killed in this fashion becomes much easier to locate for a time, since its liquid form becomes tinged with blood and its body leaves a visible trail of the stuff behind it.

Descent into Madness. Achieving revenge against its target doesn’t end a slithering tracker’s existence, nor its hunger for blood. Some slithering trackers remain aware of their purpose and extend their quest for vengeance to others, such as anyone who supported or befriended the original target. Most of the time, though, a tracker’s mind can’t cope with being trapped in liquid form, unable to communicate, and driven by the desire for blood: after a tracker fulfills its duty, insanity takes over the creature, and it attacks indiscriminately until it is destroyed.

Provavelmente não é o melhor modelo para uma corrida jogável, mas pode fornecer algumas idéias úteis.

E, finalmente, os oblexos em Tomo dos inimigos de Mordenkainen (p. 217):

By experimenting on the slimes, jellies, and puddings that infest the depths of the Underdark, mind flayers created a special breed of ooze, the oblex — a slime capable of assaulting the minds of other creatures. Cunning hunters, these pools of jelly stalk prey, searching for the memories they so desperately crave. When oblexes feed on those thoughts, sometimes killing their victims, they can form weird copies of their prey, which help them to harvest even more victims for their dark masters.

Memory Eaters. Oblexes feed on thoughts and memories. The sharper the mind, the better the meal, so oblexes hunt obviously intelligent targets such as wizards and other spellcasters. When suitable fare comes within reach, an oblex draws its body up to engulf its victim. As it withdraws, it plunders the creature’s mind, leaving its prey befuddled and confused.

Ooze Nature. An oblex doesn’t require sleep.

Deixando de lado as características, essa pode ser a melhor inspiração para como surgiu uma corrida jogável de gosma - embora você precise considerar por que / como elas não são más. Os oblexos envolvem suas vítimas, invadem sua mente e memórias e, em seguida, são capazes de se passar por esse alvo.

Tomo dos inimigos de Mordenkainen O capítulo 1 (p. 30) possui uma seção sobre benefícios demoníacos que um Mestre pode conceder a monstros e NPCs dedicados a um senhor demoníaco em particular, que você também pode usar como inspiração para traços raciais:

Wicked folk who seek power from demons are scattered across the multiverse. Some of them gather in cults, but many of them act on their own or in small groups. Whatever their organization, they are united in their desire to draw power from the bottomless evil of the Abyss.

The following entries outline boons that a DM can grant to monsters and NPCs dedicated to a particular demon lord. The entries also list signature spells associated with a demon lord. If the monster or NPC can cast spells, you can replace any of those spells with spells from that list, as long as the new spell is of the same level as the spell it replaces.

[...]

Ability Score Adjustment: Up to a +8 bonus to Constitution, with an equal penalty to Intelligence, Wisdom, and Charisma

Signature Spells: Grease (1st level), web (2nd level), gaseous form (3rd level)

The Faceless Lord’s followers are bizarre loners who prefer the company of slimes and oozes to other creatures. They gain the hardiness of a slime at the cost of their minds. Lesser followers gain the Liquid Movement trait. The most dedicated devotees of ooze also gain the Slimy Organs trait.

Liquid Movement. As an action, this creature can move up to 20 feet through spaces no more than an inch in diameter. It must end this movement in a space that can accommodate its full size. Otherwise, it takes 5 force damage and returns to the space where it began this movement.

Slimy Organs. This creature has resistance to bludgeoning, piercing, and slashing damage from nonmagical attacks.

Whenever this creature suffers a critical hit or is reduced to 0 hit points, all creatures within 5 feet of it take acid damage equal to its number of Hit Dice.

Obviamente, você deve manter o equilíbrio em mente ao considerar a possibilidade de conceder algum desses benefícios e como equilibrar quaisquer benefícios adicionais em relação a outras raças (talvez concedendo outras desvantagens). O ajuste do escore de habilidade provavelmente seria desequilibrado; as magias de assinatura podem ser permitidas se você seguir o formato de outras características raciais de conjuração; Movimento líquido pode ser permitido desde que você projete / modifique a campanha com ela em mente; e órgãos viscosos provavelmente superariam.

Em suma, é provável que você evite dar muitas dessas características / habilidades a uma corrida jogável, mas são coisas que você deve ter em mente ao fazer uma corrida jogável. É claro que você pode evitar incorporar a maioria dessas características, principalmente se a sua campanha estiver definida em algum lugar que não seja nos Forgotten Realms (aos quais a conexão da Juiblex está ligada).