Illithid names are widely varied and adopted from many cultures.
Male Names: Sangalor, Zoidberg, Chuul
Female Names: Marianne, K’thula, Geverstrem
Family Names: Illithids do not have families or clan identifiers.
Powerful minds are the hallmark of the illithid. They are mostly psions and scientists. They created scientific forms of magic, which allows people to learn and harness magic.
Ability Score Increase: Your Intelligence score increases by 2.
Age: As humans.
Alignment: Shattered Illithid have a wide variety of alignments. Unlike other worlds, the shattering left them as individuals, with no gestalt or inherent desire to enthrall.
Tentacles: Illithid tentacles are incredibly strong and are used in the feeding process, rending flesh and cracking skull to reveal tasty grey matter. You can you add your Intelligence modifier (instead of Strength) to grappling checks with tentacles. You may only grapple one creature at a time. An illithid also can use Int as a prerequisite for the grappler feat.
Extract: An illithid that has grappled a target can make an attack to attempt to extract the brain of a grappled subject. The illithid makes a melee attack + Int. If successful, the illithid does 1/2 level (round down)D10 Psychic Damage. If the target is reduced to 0hp, the target dies of brain extraction.
Language: You can speak, read, and write Common and one other language of their choice. Illithids have no spoken language of their own, but they do have elaborate body language based upon the movements of their tentacles and the hissing and gnashing of their maw.
Subrace: There are two types of illithid: the mind flayer which is more numerous and the thoon, which is rare.
Psychic sensitives, once masters of thralls beyond number. The shattering left them psychic, but individual.
Ability Score Increase: Your Wisdom score increases by 1.
Mind Bolt: As blast of psychic energy that briefly stuns foes. A Mind Flayer gains the cantrip Mind Bolt (see below). The attack bonus is Proficiency + Int.
Telepathy: A Mind Flayer can use the spell Detect Thoughts once per long rest.
Physically powerful, built for combat and protection. Trained in the construction of psychic weaponry and body manipulation.
Ability Score Increase: Your Constitution score increases by 1.
Psychic Shield: A thoon with a free hand can construct a shield of psychokinetic force. This shield improves AC by 2 and doesn’t require proficiency to use.
Psychic Weapon: A thoon can manifest a weapon of psychokinetic force. This weapon can take any shape (and has all the properties of such a weapon). The weapon requires proficiency to be wielded effectively. When inspired (using inspiration), you can imbue the weapon with +1 magical bonus for a number of rounds equal to your Constitution modifier. (You give up the advantage roll in favour of the +1 bonus to rolls).
0 level cantrip
Casting Time: 1 action
Range: 60 feet
A surging bolt of psychic energy lashes out at the target, very briefly stunning them. Make a ranged spell attack against the target. On a hit, it takes 1d8 psychic damage and can not use reaction abilities until the start of your next turn. This power increases by 1d8 damage at 5th level (2d8), 11th level (3d8) and 17th level (4d8).