Deep Gnome

A constant hum of busy activity pervades the warrens and neighborhoods where gnomes form their close-knit communities. Louder sounds punctuate the hum: a crunch of grinding gears here, a minor explosion there, a yelp of surprise or triumph, and especially bursts of laughter. Gnomes take delight in life, enjoying every moment of invention, exploration, investigation, creation, and play.
Deep gnomes, or svirfneblin, are natives of the Underdark and are suffused with that subterranean realm’s magic. They can supernaturally camouflage themselves, and their svirfneblin magic renders them difficult to locate. These abilities have enabled them to survive for generations among the perils of the Underdark.

Creating a Gnome

Ability Score Increase. Your Intelligence score increases by 2.
Creature Type. You are a Humanoid.
Age. Gnomes mature at the same rate as humans, and most are expected to settle into adult life around the age of 40. They can live to 350 years on average, but it's not too uncommon for them to reach 500 years of age.
Size. Gnomes are between 3 and 4 feet tall and weigh around 40 pounds. Your size is Small.
Speed. Your base walking speed is 25 feet.
Darkvision. Accustomed to life underground, 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.
Gnome Cunning. You have Advantage on all Intelligence, Wisdom, and Charisma saves against magic.
Languages. You can read, speak, and write Common and Gnomish.

Deep Gnome Traits

Mordenkainen Presents: Monsters of the Multiverse Variant

Ability Score Increase. Your Dexterity score increases by 1.
Darkvision. You can see in dim light within 120 feet of you as if it were bright light and in darkness as if it were dim light. You discern colors in that darkness only as shades of gray.
Gift of the Svirfneblin. Starting at 3rd level, you can cast the @Disguisespell with this trait. Starting at 5th level, you can also cast the Nondetection spell with it, without requiring a material component. Once you cast either of these spells with this trait, you can’t cast that spell with it again until you finish a long rest. You can also cast these spells using spell slots you have of the appropriate level.

• Intelligence, Wisdom, or Charisma is your spellcasting ability for these spells when you cast them with this trait (choose when you select this race).
  

Svirfneblin Camouflage. When you make a Dexterity (Stealth) check, you can make the check with advantage. You can use this trait a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

Elemental Evil Player's Companion Variant

Ability Score Increase. Your Dexterity score increases by 1.
Superior Darkvision. Your Darkvision has a radius of 120 feet.
Stone Camouflage. You have Advantage on Dexterity (stealth) checks to hide in rocky terrain.

Deep Gnome Civilizations

The Doldoth Gnomes

Deep Gnome Characteristics

Source: Elemental Evil Player's Compendium

Racial Options

There are a few options to make your character fit the ideas you may have. The Ability Score Increase, Size, and even Languages can all be customized to better fit your character's history. Maybe you come from a very hardy people, like the Dwarves, but your character can't handle even the slightest cold breeze, but they make up for it with their incredible intellect. You could have been born of the tall and long Elves, but you find yourself barely coming up to some of their hips. Your Goblin may have been adopted by a couple of loving Genasi and they taught you to speak Primordial instead of Goblin. The options listed under your chosen race are just suggestions to easily fit your character within their culture's society, but you can change things up to make your character truly yours. There may be limitations set by the DM; rarely will you find a Large Fairy or a Tiny Goliath, but if you have a good story-driven reason for different character options, anything can be possible. Below are open-ended options for customizing your race.
Ability Score Increase. Increase one ability score by 2, and increase a different one by 1.
Size. Your size is within one size option of your race's average size.
Languages. You can speak, read, and write Common and one other language that you and your DM agree is appropriate for the character.

Choosing a Class

Artificer
Barbarian
Bard
Cleric
Druid
Fighter
Monk
Paladin
Ranger
Rogue
Sorcerer
Warlock
Wizard