Aliens

Cruachite

Home Planet: Cromcruach
First Contact: A century ago
Appearance: Humanoid. Could be mistaken for a human in low light or from a distance. Have only three fingers on each hand, and three toes on each foot. Mouths wide and oddly shaped. Eyes have x-shaped pupils. Skin is often covered in patches of a harmless symbiotic mold.
Features: They are born sexless but will choose to become one of two sexes (sire or bearer) when they come of age. Can change sexes, but only after spending a certain amount of time as the previous sex. Must wear special breathing apparatus on other planets.
Notes: Require translation devices when communicating with other races, due to their unique language

The Datamind

Home Planet: Unknown
First Contact: During WWIII
Appearance: They have no physical body. They take the form crystalline, snowflake-like shapes when appearing on screens or in holograms.
Features: They successfully converted themselves into pure data while humans were building their first civilizations. To communicate and interact with others, they use various devices.
Notes: The first aliens to make contact with humans

Kochabian

Home Planet: Unnamed moon of a gas giant
First Contact: One hundred years ago
Appearance: Resemble giant moths with tentacles instead of legs, and spider-like fangs.
Features: Originally eusocial. Good at organization and management. Reproduction is a privilege in Kochabian society
Notes: Often recruited for white-collar jobs

Niobian

Home Planet: Niobe
First Contact: First manned extra-solar mission
Appearance: Semi-amorphous, iridescent, and androgynous humanoids. What appears to be extremely long hair on their heads is actually thousands of prehensile tentacles.
Features: They are highly evolved. They have 12 different sexes, and 36 genders.  They can alter their facial and body features to resemble those of other humanoids. They mostly communicate via telepathy and empathy.
Notes: They often act as negotiators and diplomats. Niobian society is post-scarcity, the first example to be found outside of science fiction.

Tatzel

Home Planet: Randigris
First Contact: One hundred years ago
Appearance: Reproductive castes are feline in appearance, with long thick tails replacing legs. Drone caste is sexless and reptilian in appearance, with four limbs
Features: Semi-eusocial. Females are at the very top of Tatzel society, followed by males, and drones at the bottom
Notes: Tatzel society has similarities to that of bonobos, with the males and females resolve conflict through sex

Tonoe

Home Planet: Randigris
First Contact: One hundred fifty years ago
Appearance: Humanoid. Have human-looking heads and upper torso torsos, but with brightly colored skin, and feathers replacing hair. Hands are four-fingered and clawed, while legs and feet resemble those of a dromaeosaur. Have long feathered tails. Feathers also cover forearms and shins. Eyes have slit pupils, and mouth has small but noticeable fangs. Females are taller, stronger, and more colorful than males.
Features: Matriarchal. Females are deeply protective of males, and reluctant to let them do anything dangerous. All adult Tonoe, in addition to a mate of the opposite sex, also have a same sex lover known as a pleasure mate
Notes: They have a code of honor that most of the race follows. Like open spaces and curved structures. Speak Earth languages with what sounds like an Australian accent.