Nechani
Peaceful

In 2372, Voyager first encountered the Nechani. The Nechani are a deeply religious people. During a tour of one of their temples, Kes was hit by an energy burst, which rendered her unconscious. In order to save her, Janeway had to go through one of the Nechani's purification rites
(Sacred Ground)

Nezu
Peaceful

The Nezu homeworld was experiencing asteroid showers when Voyager encountered them in 2373. They found that the Ethanian Order was responsible. They have technology to create meteor showers or other "natural" disasters, on different planets which they take over when the inhabitants evacuate
(Rise)

Night Aliens
Peaceful

The Night Aliens were living a peaceful existence in the 'void' when the Malon began poisoning them with Theta radiation by dumping their anti-matter waste all over their space. Janeway helped them to close the vortex the Malon were using to access the void and protect their space from the Malon
(Night)

Nihydron
Peaceful

The Nihydron allied themselves with Voyager and the Mawasi to destroy the Krenim timeship responsible for repetedly altering the history in Krenim space
(Year of Hell)

Norcadian (Species 689)
Peaceful

The Norcadian people enjoy watching 'Tsunkatse' matches where people are forced to play against each other against their will. A lot of the planet's revenue comes from Tsunkatse, which means that the politicians weren't very helpful when Seven was abducted and forced to play the game
(Tsunkatse)

Nygean
Peaceful

Voyager encountered the Nygean in 2377. They helped them transport prisoners after the Nygean ship had been destroyed. The Nygean legal system is based on a principle called "Vekto Valek K'Vadim" which means that the victim's family chooses the convict's sentence. If a defendant is wealthy enough, he can buy himself free from a sentence by paying a big fine to the family
(Repentance)

Nyrians
Hostile

They abducted various humanoids and stole their ships or space stations. They kept their prisoners in a ship with many different biospheres to suit the needs of the different species. The crew of Voyager was abducted in 2373 but was able to escape.
(Displaced)

Ocampa
Peaceful

The Ocampans were one of the first races that Voyager encountered when arriving in the Delta Quadrant. They are a peaceful race, which lives underground. The Nacene visited Ocampa approximately 1,000 year ago and accidentally destroyed the Ocampan atmosphere by removing all of its neucleogenic particles. This made it impossible for the planet's atmosphere to create clouds, rain or water. The Nacene felt responcible for the situation and left a chosen 'Caretaker' to provide them with food, protection and other necessities.The Ocampans have a very short lifespan, which is between nine and twelve years. They have Minor Telepathic abilities, which they use to communicate mentally, rather than verbally. The Ocampans once had greater mental abilities but they gradually stopped using them because their every need was met by the caretaker and they eventually forgot about them. Over time, the Ocampans became completely dependent upon the Caretaker. Ocampans can only have one child. The female Ocampa must have her feet rubbed by her father. Her hands then produce a mucous substance, which will lock her and her mate together for a long period, to ensure conception. During this Elogium, the woman carries the child on her back.
In 2372, Voyager encountered another caretaker, Susperia. She was once the original Caretaker's mate. She didn't agree with her mate on how to take care of the Ocampan species, and left together with a group of Ocampans, which she helped to grow stronger telepathic abilities. Kes is an Ocampa.
(Caretaker, Cold Fire, Fury)

Pralor
Hostile

A nearly extinct line of Humanoid robots created by the Pralor, a species of humanoids who no longer exist. The robots cannot produce new prototypes since each power module has an individual energy code. The Cravics, another humaniod species at war with the Pralor, created similar robots. All of the warring robots were programmed for victory, and when the Pralor and Cravic humanoids decided to call a truce, the robots terminated them and continued their battle
(Prototype)

Q
Relatively Peaceful

The Q is a powerful omnipotent species that the Federation first encountered in 2364. The Q can use their incredible powers to accomplish almost anything. The Q were responsible for carrying the Enterprise-D to system J-25 in 2365 when they first encountered the Borg. The Q also put humanity on trial in 2364 for barbaric behaviour.
Voyager first encountered the Q in 2372 when Voyager encountered a comet with a Q trapped inside. It was later determined that this Q was imprisoned in the comet since he had attempted to commit suicide, something which no Q had ever done before. Voyager encountered Q again when he needed help with stopping a civil war in the Q continuum. Q wanted to mate with Janeway to produce a child that would unite all Q once again and give hope for the future. Q ended up mating with another Q and a child was conceived. The son of Q ended up being hard to control and Q asked Janeway in 2377 to straighten the young Q up or his son would be turned into a minor species. She succeeded and the young Q was spared of a future as a single celled organism.
(Death Wish, The Q and the Grey, Q2)

Qomar
Peaceful

They live in a closed system and are not well-versed in social interaction or music. They got enthralled by the doctor's singing as he tended to their medical needs and invited the Voyager crew to visit their nearby planetary alliance.
(Virtuoso)

Quarran
Peaceful

Quarra is a planet with extensive labour shortage. They need lots of workers for their different factories and power plants. A local doctor, Kadan, decided to make money on abducting and re-program aliens that pass Quarran space. He abducted the entire Voyager crew except for Kim and Chakotay who were on an away mission, and the doctor. They had no memory of Voyager and the remaining crew had to locate and help the abducted crew to remember their true origin. The Quarran people are peaceful even though some of them (like Dr. Kadan) are ruthless. Quarran officials maintain high security to protect their guest workers and the employers are often concerned with safety
(Work Force)

Rakosan
Peaceful

The cardassian missile Dreadnought was reprogrammed by B'Elanna Torres to attack a Cardassian target. The missile was transported into the Delta Quadrant in the same way as Voyager and proceeded on it's course as if it had still been in the Alpha Quadrant. It mistook the planet Rakosa for the Cardassian target and prepared to destroy the planet. Rakosa is a heavily populated planet with peaceful inhabitants
(Dreadnought)

"Reptohumanoid creatures"
Peaceful if not provoked

Neelix and Lieutenant Paris went on an away mission to a toxic planet to replenish food supplies in 2372. Their shuttle was damaged and they had to seal themselves in a cave, when a reptohumanoid creature hatches from an egg. These creatures can only survive in a trigemic vapors atmosphere and their infants are nurtured by parents
(Parturition)

Rilnar
Unknown

The Rilnar was in conflict with the Krenim Imperium but was defeated and erased from from history in 2374 by a Krenim time ship. This action also removed a crucial antibody that the Rilnar had contributed to the Krenim DNA. This resulted in a plague that killed fifty million Krenim during the first year after the Rilnar had been erased. The Rilnar was restored to its original state when the time ship was destroyed.
(Year of Hell)

Sakari
Peaceful

After their planet was struck by the Borg in the past, the Sakari was forced to abandon the surface and move under ground. They masked their life signs as well as any technology to escape the Borg threat
(Blood Fever)

Serosian
Unknown

A species who let holograms perform the more dangerous tasks on their starships. Some (perhaps all) of the holograms are treated badly (Revulsion)

Sikaris
Peaceful

The Sikaris is an aloof species widely known for their hospitality and love for literature and stories. They use technology that can transport a starship or a person over 40,000 lightyears away by folding space, but they are prohibited by a planetary directive to share their technology with less advanced species. The technology is not compatible with federation technology.
(Prime Factors)

Species 116
Peaceful turned Hostile

Voyager met Arturis, who was one of the last of his species after his people was assimilated by the Borg. They were once gifted linguists, who were capable of understanding thousands of languages. But When Species 8472 retreated into fluidic space in 2374, Species 116 could no longer hold the Borg off. Arturis blamed Voyager for their defeat and tried to get the crew assimilated. He ended up being assimilated himself instead.
(Hope and Fear)

Species 125
Unknown

The Borg Queen was from species 125 before she was assimilated.
(Dark Frontier, Unimatrix Zero, Endgame)

Species 149
Unknown

A species with advanced medical technology that was assimilated by the Borg. Seven used their method for reversing cellular necrosis to revive Neelix.
(Mortal Coil)

Species 6339
Relatively Peaceful

They invented a virus that they infected volunteering inhabitants with and sent them out to get assimilated. The virus was designed to attack technology and spread to the Borg when the volunteers were assimilated.
(Infinite Regress)

Species 8472
Once Hostile

 
The Borg gave them the designation species 8472. First encountered in 2374, in the corridor Voyager called the NorthWest passage, within Borg space. Species 8472 were provoked when the Borg invaded their home, Fluidic Space, which is filled with organic fluid and exists in another dimension. The Borg entered their space to assimilate their bio-technology but the species was more resilient than they thought and they ended up fighting in the NorthWest passage in normal space. Species 8472 travel in one-man bio ships, which are very powerful, and can destroy a Borg cube in a few shots. Species 8472 is a highly developed, evolved, intelligent race. Their DNA code is very dense, and the most complicated that the Doctor had ever encountered. 8472 is able to release a type of virus into the bodies of victims, which slowly begins to consume them. No known drug could stop the process, until the doctor found a cure by injecting Borg nanoprobes that eliminated the virus within the bodies of the victims. He also realized that these nanoprobes could be used as a weapon to stop Species 8472.
As Voyager perceived Species 8472 a bigger threat than the Borg they offered the Borg a way to defeat Species 8472 in exchange for safe passage through Borg space. They equipped several torpedo warheads with nanoprobes, which were able to attack 8472's ships on a biological level. After destroying nearly 20 bio ships, Voyager detected that all 8472 bio-ships were heading back to fluidic space.
Voyager later realized that one bio-ship was trapped behind after the others had retreated. Voyager also detected a Hirogen ship, which was hunting the alien. Janeway tried to help the injured Species 8472 and to return him to Fluidic Space but she failed.
Voyager encountered species 8472 once again in 2375 when Voyager discovered a copy of Starfleet Academy on a planet in the Delta Quadrant. Species 8472 explained during a peace talk that they had been forced to take extreme measures to fight the Borg and were certain that all humans were as evil as the Borg because of the temporary alliance. Humans and 8427 were able to understand each other better and hopefully stop fearing each other
(Scorpion, The Gift, Prey, In the Flesh)

Species 10026
Peaceful

A species from Grid 532 that the Borg Queen tried to force Seven to help assimilate.
(Dark Horizon II)

"Scavengers, The"
Hostile

First encountered in 2377 in a natural phenomenon nicknamed the Void. The Void was an anomaly that dragged ships into a part of space that kept them from getting out. The Scavengers consisted of many different species that raided and stole valuable equipment and nutritional supplements from other ships dragged into the Void. Janeway succeeded in starting a new alliance with some of the ships in the void to help new ships against the hostile scavengers. They succeeded to escape the phenomenon by helping and sharing each other’s technology
(The Void)

Srivani
Hostile

The Srivani conducted experiments on the entire crew in 2374. They could avoid beeing seen by the crew by using a 0.5 phase variance. They are ruthless scientists that try to better their own medical knowledge by conducting these experiments or tests on alien species that pass their way
(Scientific Method)

Swarm, The
Hostile

The Swarm were first encountered in 2373. They are an insectoid race that "clamp" on to their victim's ships, draining their energy and then transport on board to eliminate the crew. They travel in swarms of hundreds of ships; energy fired at the Swarm is projected back towards the firing ship. Voyager was able to defeat the Swarm by targeting one single ship. They were connected in a lattice, which means that they were all destroyed in a chain reaction
(The Swarm)

Takari
Peaceful

Unsophisticated people with mythic prophecies predicting the arrival of holy sages will leave on "wings of fire" following the arrival of a holy pilgrim
(False Profits)

Tak Tak
Peaceful

 
The Tak Tak was a species that Captain Janeway and Neelix visited to open diplomatic talks for trading purposes in 2373. The Tak Tak uses a complex physical "language" to communicate. One of the worst insults is to put your hands on your hips
(Macrocosm)

Talaxian (Species 218)
Peaceful

Talaxians are a loyal and trusting species from the planet Talax and its moon Rinax. They value their family above all else, and celebrate the annual holiday Prixin, which is a celebration of the family. They think that you travel to the Great Forest when you die, where you will meet up with your deceased friends and family. Talaxians have two hearts, two lungs and, according to Seven, a cranial plate suitable for assimilation. Voyager encountered a Talaxian colony in 2377. Neelix wanted to help his people and decided to stay with them, leaving Voyager for good
(Caretaker, Investigations, Fair Trade, Homestead)

Taresian
Hostile

The planet Taresia has a largely female populace. The Taresian women trick men to come to their planet to marry them. They then use the men to extract enough genetic material to conceive children
(Favourite Son)

Tarakis
Unknown

The Tarakis once raised a memorial sending out synaptic neurogenic pulses throughout the Taraki system. People who enters the system will experience memories of a massacre of 82 Nikon civilians. (Memorial)

Telsian
Peaceful

A species that was cheated by the con artists pretending to be Janeway and her senior officers.
(Live Fast and Prosper)

Trabe
Hostile

The Trabe once held the Kazon as slaves, until the Kazon rose up against them. Since then, the Trabe has been in exile
(Alliances)

Uxali
Hostile

Technology from the probe called Friendship One devastated the Uxali home world Uxal and rendered the atmosphere toxic. Voyager restored the atmosphere in 2378.
(Friendship One)

Vaadwaur
Hostile

The Turei used plasma-based weapons to destroy the Vaadwaur civilization in 1484 while fighting for the nearby subspace corridor network. The surviving people decided to hide in stasis pods until the planet was habitable again but the re-animation process was damaged during their hibernation. After Voyager had re-animated the Vaaduwaur population they decided that they would take over Voyager to live more comfortably there
(Dragon's Teeth)

Vaska
Relatively Peaceful

Was involved in a civil war that nearly wiped out the Kyrian race. Voyager was accused of ruthlessly aiding the Vaska in order to get access to a nearby wormhole
(Living Witness)

Vidiian
Hostile

The Vidiians were first encountered in 2371, when Neelix had his lungs stolen while on an Away mission looking for dilithium deposits. Luckily, for Neelix, the Doctor was able to use "holographic lungs" to keep Neelix alive. Captain Janeway learned that these Vidiians must harvest other species organs to sustain themselves. The Vidiians were almost entirely wiped-out by a fatal plague, called the Phage, which causes their organs to breakdown. Their highly sophisticated medical transport technology makes it quite simple to harvest all internal organs they need to survive. Before the Phage crippled the Vidiian race, they were scholars, civilized and had a rich, defined culture. They have scientists working constantly on a cure to the phage. In 2371, the Vidiians kidnapped B’Elanna, Tom and Lieutenant Durst because they thought they could use B'Elannas DNA to develop a cure. Voyager has now passed through the Vidiian territory.
(Resolutions, Phage, Faces, Deadlock, Lifesigns, Fury)

Vhnori
Peaceful

The Vhnori was encountered when Ensign Kim was dragged into a dimensional distortion and transported to the Vhnori homeworld. They send their dead, and people who cannot contribute to the society any longer, through a ceremonial burial pod. Thir souls are supposed to reach the next emmanation, or afterlife, which the Vhnori know very little about
(Emanations)

Voth
Relatively Peaceful

The Doctor analized the Voth and found common strands in both Voth and Human DNA. He discovered that the Voth had originated from Earth millions of years ago and had eventually evolved fom dinosaurs into a complex species. It seemed that they had been able to escape the planet before the asteroid collided with Earth and wiped out the Dinosaurs. A Voth scientist, Gegen, attempted to convince his people that the Voth had travelled into the Delta Quadrant to find a new home world, but the Voth were un-willing to accept it. They didn't want to admit that they were really refugees from another planet.
(Distant Origin)

Yallitians
Peaceful

A species with three spinal columns known for their engineering skills. Known only to Neelix
(Phage)

Zahl
Peaceful

The Zahl was a technologically advanced species in one of many possible Year of Hell timelines. They defeated the Krenim Imperium after it had been crippled by a plague that followed their elimination of the Rilnar. They were later deleted from history by the Krenim time ship.
(Year of Hell)