GOLDILOCKS ALIENS / BATTLESHIP ALIENS

Planet of Origin:Goldilocks planet, in the Milky Way galaxy

The Battleship aliens are a sentient species that developed an advanced civilisation with space faring capacity.

The are vaguely humanoid. Their hands have four opposable finger and their feet have clawed tows. They sport both mammal and reptilian features, Their face is vageuly humanlike but with less pronounced features, They are blad but possess a set of spikes all over their chin that looks that is reminiscent of a goatee beard. They are sensitive to bright lights and dislike daylight such as we have on Earth.

A scouting party came to Earth in 2012 in response to a signal from mankind had been received on their homeworld. Their goal was to establish if the planet was worth settlement. This invasion force which landed near Hawai was disposed off by the humans.

Source: Battleship movie

PRECURSORS

The Precursors are a non humanoid sentient species that developed an advanced spacefaring civilisation. Their civilization was based around the Mantle, a belief hat it was their role to protect all life in the galaxy. They presumably monitored the evolution of other sentient species throughout the galaxy, intervening in ways that ensured their civilizations would follow paths of peace, free of conflict. They were chased and destroyed by one of those younger species, the forerunners, in a war that took place some 150 000 years ago, presumably upon learning that they had chosen the humans as heirs to the Mantle instead of them. The Precursors unleashed the Flood to avenge this act of agression.

Precursors are believed to be"very large", with 4 upper limbs and 2 legs. Also having an "ugly head shaped like arthropods" - like spiders or crabs or scorpions - they have oval, faceted slanted eyes and a "flat face". Coming from the back of the head is a long tail with a 2 meter barb coming out of it but no visual record of individuals of the species exist as of now.

Source: Halo Universe,

FORERUNNERS / HOLY ONES / ANCIENTS / CREATORS

Planet of Origin: Ghibalb, a planet  located in the outer edges of the Orion complex. Once a beautiful, verdant paradise of a planet, it was cleansed of all life when an experiment in stellar engineering accidentally caused several nearby stars to supernova. It is now heavily irradiated and uninhabitable.

The Forerunners are a sentient species that developed an advanced FTL interstellar civilisation and praticed world building. They are responsible for construction of the 2 Arks structures that are used to ringworld-type fortress (from 10 000km  to 30 000km in diameters) that formed the Halo array around the galaxy. The Array was designed to kill all sentient life in the galaxy which was not protected inside specially designed Dyson-type shield worlds and therefore rid the Milky Way of the Flood parasitic lifeform.

While not record of the Forerunner's appearance remains, their battle armors show them to have a humanoid shape disturbingly close to the human form.

A very advanced civilization, they came to power after the destruction of another race, known to them as the Precursors. The Forerunner believed that the Precursors were responsible for their creation. Soon after, the Forerunners became the dominant species in the galaxy, their empire spanning over three million fertilized and inhabited worlds. The Forerunners reached their peak before activating the Halo Array around 100,000 years ago in the closing days of the Forerunner-Flood war.

Their civilization was based around the Mantle, a belief they inherited this belief from the Precursors that it was their role to protect all life in the galaxy. They presumably monitored the evolution of other sentient species throughout the galaxy, intervening in ways that ensured their civilizations would follow paths of peace, free of conflict. One such occasion is the devolution of the prehistoric human empire officially to prevent further conflict emanating from what they considered a "violent species" some 110 000 years ago, but officiously to prevent them from taking their rightful place as the Precursor's heirs to the Mantle. After their superiority was insured, the Forerunners reached a point of disarmament, believing they no longer needed weapons in their rule of the galaxy, which ultimately weakened them when the Flood attacked.

When the Forerunners were unable to contain the Flood outbreak, the galaxy entered a state of war.  However, all their tactics, were they to turn star novae to eradicate infected systems, proved only to slow, but never stop the expansion of the Flood. They realized that the only way to stop the Flood was to deprive it of any and all hosts, thus eliminating its potential to grow. Eventually, the Forerunners created the Halo Array, a weapon of last resort designed to starve the Flood to death by killing all sentient life with enough biomass to sustain them. 100 000 years ago, after having exhausted every alternative, they ctivated the Halo array, killing themselves and all sentient life of sufficient biomass in the Milky Way, with the exception of those species safely placed on the Ark. After the Array was fired and the Flood had been eliminated, the Forerunners left behind an automated system of automatons, much like the Sentinels, and AIs to spearhead the reseeding of the galaxy with those data logs, embryos, and specimens contained on the Ark.

The Forerunners are adored like gods by the alien league known as the Covenant. The fact that the Forerunners appeared to be genetically related to the humans explains why the Covenant seeks to exterminate humanity, knowing that they are the Forerunner's designated heirs and would undermine their power.

Source: Halo Universe,
adapted from the Halo Wikia's  Forerunners and other relevant entries.

ENGINEERS / SPACE JOCKEYS / OSSIANS / PILOTS / MALA'KAK / GARDENERS / COLLECTORS

The Engineers are a sentient species which developed an advanced space faring civilisation, became expert in bioengineering. They look like two meters tall white skinned overmuscled bald humans with dark eyes. Their DNA matches that of Earth's humans.

They are believed to have seeded other worlds and influenced the development of other lifeforms.

They are believed ot have come to Earth at some point in the distant past, as some cave paintings and carvings clearly state by showing the position of what is believed to be either their homeworld or their nearest outspost thru primitive starmaps. It is to be noted that those starmap represent the same stars configuration as the ones found on the starmap drawn by Betty Hill under hypnosis after having been supposedly abducted by aliens from Zet Reticuli.
Some conjecture that they may have either:
A) created mankind or influenced its development by spreading their DNA in Earth's water with the help of a mutagen agent of their making
B) been responsible, by the same means, of bringing life to Earth.
The seeding of Earth, whenever it took place and whatever its effects were, was done through a ritual suicide of an Engineer ingesting a grey goo, a mutagen compound which dissociated its cellular structure in a matter of seconds. Its remnants then flowed in Earth's running water. Theories suggest that this took place at Victoria's waterfalls in Africa.
Other theories say that they sent an emissary to Earth 2000 years ago to ensure that humanity was on right path and that he was crucified. They then decided to wipe out the human species as it was deemed dangerous.
Other theories, taking the Barney and Betty Hill abduction as evidence, reject that the Engineers wanted to wipe out humanity as they seem ot have visited the place with purely scientific purposes in the late 20th century.
The Engineers are known to have possessed a research facility dedicated to bioengineering and bioweaponry on  the planet known to humans as LV-223 (as indicated on primitve starmaps found on Earth), one of three moons of a ringed gas giant, orbiting the star Gleise 86, some 35 light years aways from Earth. It is believed that, they had plans were made to wipe out all life on Earth and start anew by bombing the planet with grey goo containers 2000 years ago. The project was put to a stop when something went wrong with their creation and the whole colony was wiped out. Another Engineer ship is known to have crashed on Acheron (LV-426) the second of three natural satellites that orbit the gas giant Calpamos,  the fifth planet from the star Zeta 2 Reticuli, some 37 light years away from Earth. If this ship came from LV-223, while most likely, remains unknown. Rather than transporting grey goo pods in its cargo bay, it was transporting Xenomorph eggs. Wether those eggs had been placed there by Engineers of Xenomorphs remains subject to debate.

Source: Prometheus movie, Alien / Predator Universe , Xenopedia Entry

Note 1: It is interesting to note that the Ancient Humanoids presented in the Star Trek Universe had a similar seeding program. For the little that was seen of them, they also shared some ressemblance with the Engineers. The beings are said to be  presumably the first humanoid species to evolve in the Milky Way galaxy, some four and a half billion years before the common era. Their true name lost since time immemorial, they have also come to be known as the Ancient Progenitors, and the Galenites, a name derived from the man whose work led to their discovery, Dr. Richard Galen. (TNG: "The Chase", Star Trek: Dark Horizon, Star Trek: Pendragon) During the height of their existence, they explored the galaxy, but found no lifeforms like themselves. Realizing that their species would one day cease to be, they seeded many primordial planets with the building blocks of life, encoding the DNA so that it would evolve into forms similar to their own. Earth was one such planet.
Note 2: It is also interesting to note that in the film Mission to Mars, the  martians are revealed to have seeded Earth with thesame results - while the method is not show - before they were to depart the solar system to populate other worlds at the time Mars was to be hit by a giant asteroid, as shown here. For waht was seen of them, the martians were humanoid but apart from that, did not look that much like humans or engineers.

VEDRANS

Planet of Origin: Tarn-Vedra, in the Andromeda Galaxy

The Vedrans are an advanced species that developed an advanced FTL space-faring expansive civilisation. 

They are responsible for founding the Vedran Empire and later the Systems Commonwealth. which span the Andromeda galaxy, the Milky Way and the Triangulum Galaxy.

They resemble blue skinned centaurs, with four powerful legs and a humanoid upper body. Their blood is blue. They have no hair on their boy but males have long, brightly colored crests of feathers which cover their heads and spines. They are a matriarchal society, where females act as the leaders of the family unit or herd. A male first owes loyalty to his mother's herd, then his mate's. Herds are organized into tribes and tribes into nations with all Vedran nations being ruled by an Empress, the spiritual and political head of the species. Males tend to be less intelligent and more aggressive than females. They outnumber females by approximately six to one and each female typically keeps several Vedran males in her family unit, with the Prime male having mating privileges, while the other males perform helper functions. 

Source: Andromeda v series

T