Homebrew Flumph Species Details

The mysterious flumphs drift through the Underdark, propelled through the air by the jets whose sound gives them their name. A flumph glows faintly, reflecting its moods in its color. Soft pink means it is amused, deep blue is sadness, green expresses curiosity, and crimson is anger. Flumphs communicate telepathically. Though they resemble jellyfish, flumphs are sentient beings of great intelligence and wisdom, possessing advanced knowledge of religion, philosophy, mathematics, and countless other subjects. Flumphs are sensitive to the emotional states of nearby creatures. If a creature's thoughts suggest goodness, a flumph seeks that creature out. When facing creatures that exude evil, a flumph flees. Flumphs feed by siphoning mental energy from sentient creatures, and they can be found lurking near such communities. As passive parasites, they take only the mental energy they need, and most creatures feel no loss or discomfort from such feeding. Consuming psionic energy reveals the thoughts and emotions of the creatures on which the flumph feed. Since so many of those creatures are evil, flumphs are often subjected to thoughts, emotions, and hungers that sicken their pure nature. When flumphs encounter good-hearted adventures, they are eager to share the dark secrets they have learned in the hopes of casting down their evil sources of energy, even if doing so means they must seek out new sources of nourishment. Flumphs live in complex and organized groups called cloisters, within which each flumph has a place and purpose. These harmonious groupings have no need for leaders since all flumphs contribute in their own way. 

Flumphs don't normally bother with names as they communicate through their thoughts with one another but when talking with members of other races they will adopt a name based on the race of the creature for their convenience. However, some flumphs are known to adopt simple Common/Undercommon names so they are more easily reconsidered by other races.

Male: Alpha, Ander, Beta, Blath, Bran, Frath, Gamma, Geth, Lander, Luth, Malcer, Stor, Taman, Urth.

Female: Amafrey, Betha, Cefrey, Kethra, Laal, Mara, Olga, Silifrey, Tex, Westra

The mysterious flumphs drift through the Underdark propelled through the air by the jets whose sound gives them their name.
Ability Score Increase. Your Dexterity score increases by 2 and your Wisdom and Intelligence scores increase by 1.
Age. Although flumphs reach physical maturity at about the same age as humans, the flumph understanding of adulthood goes beyond physical growth to encompass worldly knowledge. A Flumph typically claims adulthood around the age of 20 and can live to be 350 years old.
Alignment. Almost all flumphs are lawful good, however, there are some who might follow more chaotic or evil paths, influenced by the minds they've fed on.
Size. Typical flumphs weigh 15 pounds and are 3 feet across. Your size is Small.
Speed. Your base walking speed is 5 feet. You have a flying speed of 30 feet.
Aberrant Biology. Your creature type is aberration.
Advanced Telepathy. You can communicate mentally with another creature that knows at least one language within a 60-foot radius. This creature doesn't need to share a language with you but unless they have telepathy themselves they can only receive and respond but can't initiate or terminate a telepathic conversation. You must be conscious to use this trait and cannot telepathically communicate with multiple creatures at once. In addition, you can perceive the content of any telepathic communication used within 60 feet of you, and you cannot be surprised by creatures with any form of telepathy.
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.
Knowledgeable. You are proficient in either the Arcana, History or Religion skill.
Prone Deficiency. If you are knocked prone, roll a d4. On an odd result, you land upside-down and are incapacitated. At the end of each of your turns, you can make a DC 10 Dexterity saving throw, righting yourself and ending the incapacitated condition if you succeed.
Psionic Sensitivity. While your psionic sensitivity grants you abilities most wouldn't have, it also causes you to be weak to the psionic abilities. You are vulnerable to psychic damage.
Psionic Siphon. While resting within telepathic range of a sentient creature you may siphon off their mental energy. You require a full uninterrupted hour to do this and when complete you are considered to be fed for the next 24 hours, the affected creature is not aware of you doing this and receives no side effects of being siphoned off. However, when you completed this siphoning you may feel the emotions and thoughts that creature had when you fed off it. Roll a d4, on an even result you learn, a small piece of information maybe pertaining to their backstory, their current emotional state, something that is bothering them, a particular fear they have, something they desire or a certain goal they wish to achieve. The choice is up to your Dungeon Master.
Telepathic Shroud. You are immune to any effect that would sense your emotions or read your thoughts, as well as all divination spells.
Languages. You can understand Undercommon but can't speak it. You have telepathy within 60 feet.

All credit goes to the Flumph 5e race on dandwiki.com. I simply transferred it to homebrew for myself. Many thanks!

Flumph Traits

Trust a Flumph. —X The Mystics First Rule of Dungeon Survival

Ability Score Increase

As a flumph, you are knowledgeable, wise, and quick. Your dexterity score increases by 2 and your intelligence and wisdom scores both increase by 1.

Darkvision

Since flumphs live in the Underdark, they have darkvision out to 60 feet.

Languages

Flumphs understand Undercommon but cannot speak it, instead they possess telepathy out to 60 ft.

Knowledgeable

Flumphs know one skill from Arcana, History, or Religion.