Yuan-Ti Pureblood (from Volo's)

• Ability Score Increase: Your Charisma score increases by 2, and your Intelligence score increases by 1.

• Age: Purebloods mature at the same rate as humans and have lifespans similar in length to theirs.

• Size: Purebloods match humans in average size and weight. Your size is Medium.

• Speed: Your base walking speed is 30 feet.

• Darkvision: You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.

• Innate Spellcasting: You know the Poison Spray cantrip. You can cast Animal Friendship an unlimited number of times with this trait, but you can target only snakes with it. Starting at 3rd level, you can also cast Suggestion with this trait. Once you cast it, you can't do so again until you finish a long rest. Charisma is your spellcasting ability for these spells.

• Poison Affinity: You gain proficiency with the poisoner's kit.

• Poison Immunity: You are immune to poison damage and the poisoned condition.

• Languages: You can speak, read, and write Common, Abyssal, and Draconic.

• Abysal Protection: As a reaction to being forced to make a saving throw against spells or other magical effects you can give yourself advantage when making those saving throws. You can use this ability a number of time equal to your Charisma modifier.

Naga (from Amonkhet)

• Ability Score Increase: Your Strength, Dexterity and Intellect scores each increase by 1

• Age: Like humans, naga reach adulthood in their late teens. They show no signs of aging beyond that point except for growing larger, so in theory, a naga could live well over a century.

• Size: Naga stand about 5 feet tall when upright, but the total length of their bodies, head to tail, ranges from 10 to as much as 20 feet. Your size is Medium.

• Speed: Your base walking speed is 30 feet.

• Speed Burst By lowering your body to the ground and propelling yourself with your arms, you can move more quickly for a time. As a bonus action on your turn, if you have both hands free, you can increase your walking speed by 5 feet until the end of your turn.

• Natural Weapons: Your fanged maw and constricting serpentine body are natural weapons, which you can use to make unarmed strikes. If you hit with your bite, you deal piercing damage equal to 1d4 + your Strength modifier, and your target must make a Constitution saving throw (DC 8 + your proficiency bonus + your Constitution modifier). On a failed save, the target takes 1d4 poison damage. If you hit with your constrict attack, you deal bludgeoning damage equal to 1d6 + your Strength modifier, and the target is grappled (escape DC 8 + your proficiency bonus + your Strength modifier). Until this grapple ends, the target is restrained, and you can't constrict another target.

• Poison Immunity: You are immune to poison damage and can't be poisoned.

• Poison Affinity: You gain proficiency with the poisoner's kit.

• Languages: You can speak, read, and write Common and Naga.

Warforged (HB)

The warforged were built to fight in the Last War. The first warforged were mindless automatons, but House Cannith devoted vast resources to improving these steel soldiers. An unexpected breakthrough produced fully sentient soldiers, blending organic and inorganic materials. Warforged are made from wood and metal, but they can feel pain and emotion. Built as weapons, they must now find a purpose beyond the war. A warforged can be a steadfast ally, a cold-hearted killing machine, or a visionary in search of purpose and meaning.

• Ability Score Increase: Your Constitution score increases by 2, and one other ability score of your choice increases by 1.

• Size: Medium

• Constructed Resilience: You were created to have remarkable fortitude, represented by the following benefits: You have advantage on saving throws against being poisoned, and you have resistance to poison damage. You don't need to eat, drink, or breathe, and you are immune to disease. You don't need to sleep, and magic can't put you to sleep.

• Sentry's Rest: When you take a long rest, you must spend at least six hours of it in an inactive, motionless state, rather than sleeping. In this state, you appear inert, but it doesn't render you unconscious, and you can see and hear as normal.

• Integrated Protection: Your body has built-in defensive layers, which can be enhanced with armor: You gain a +1 bonus to Armor Class. You can don only armor with which you have proficiency. To don armor, you must incorporate it into your body over the course of 1 hour, during which you remain in contact with the armor. To doff armor, you must spend 1 hour removing it. You can rest while donning or doffing armor in this way. While you live, your armor can't be removed from your body against your will.

• Languages: You can speak, read, and write Common and one other language of your choice.

Simic Combine Hybrid

For this race I simply chose to expand the mutation choices available for the player to select.

Vampire (Plane Shift Ixalan)

• Ability Score Increase. Your Strength, Dexterity, and Charisma scores each increase by 1.

• Age: Vampires don’t mature and age in the same way that other races do.

• Size: Vampires are the same size and build as humans. Your size is Medium

• Speed: Your base walking speed is 30 feet.

• Darkvision: Thanks to your heritage, you have superior vision in dark and dim conditions. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

• Vampiric Resistance: You have resistance to necrotic damage.

• Bloodthirst: You can drain blood and life energy from a willing creature, or one that is grappled by you, incapacitated, or restrained. Make a melee attack against the target. If you hit, you deal 1 piercing damage and 1d6 necrotic damage. The target’s hit point maximum is reduced by an amount equal to the necrotic damage taken, and you regain hit points equal to that amount. The reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.

• Feast of Blood: When you drain blood with your Bloodthirst ability, you experience a surge of vitality. Your speed increases by 10 feet, and you gain advantage on Strength and Dexterity checks and saving throws for 1 minute.

• Languages: You can speak, read, and write Common and one language of your choice.

Satyr (Theros)

• Ability Score Increase: Your Charisma score increases by 2, and your Dexterity score increases by 1.

• Age: Satyrs mature and age at about the same rate as humans.

• Alignment: Satyrs delight in living a life free of the mantle of law. They gravitate toward being good, but some have devious streaks and enjoy causing dismay.

• Size: Satyrs are slightly shorter than humans, averaging about 5 feet tall. Your size is Medium.

• Speed: Your base walking speed is 35 feet.

• Fey: Your creature type is fey, rather than humanoid.

• Ram: You can use your head and horns to make unarmed strikes. If you hit with them, you deal bludgeoning damage equal to 1d4 + your Strength modifier.

• Legendary Cunning. You have advantage on all Intelligence, Wisdom, and Charisma saving throws against magic.

• Mirthful Leaps: Whenever you make a long or high jump, you can roll a d8 and add the number rolled to the number of feet you cover, even when making a standing jump. This extra distance costs movement as normal.

• Reveler: You have proficiency in the Performance and Persuasion skills, and you have proficiency with one musical instrument of your choice.

• Languages: You can speak, read, and write Common and Sylvan

Orc (from Volo's guide)

• Ability Score Increase: Your Strength score increases by 2, and your Constitution score increases by 1.

• Alignment: Orcs are vicious raiders, who believe that the world should be theirs. They also respect strength above all else and believe the strong must bully the weak to ensure that weakness does not spread like a disease. They are usually chaotic evil.

• Size: Orcs are usually over 6 feet tall and weigh between 230 and 280 pounds. Your size is Medium.

• Speed: Your base walking speed is 30 feet.

• Darkvision: Thanks to your orc blood, you have superior vision in dark and dim conditions. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

• Tribal Lore: You have proficiency in two of the following skills of your choice: Animal Handling, Insight, Intimidation, Medicine, Nature, Perception and Survival.

• Powerful Build. You count as one size larger when determining your carrying capacity and the weight you can push, drag, or lift.

• Languages: You can speak, read, and write Common and Orc. Orc is a harsh, grating language with hard consonants. It has no script of its own but is written in the Dwarvish script.