| Name | Source | Type |
|---|---|---|
| Baalols | Perry Rhodan | |
| Babel fish | The Hitchhiker's Guide to the Galaxy | A universal translator; a small yellow leech-like fish that telepathically translates all languages into one the wearer knows after inserting it in his ear. |
| Badoon | Marvel Comics | |
| Bahmi | Rift: Planes of Telara | Descendants of humans and air spirits. Large blue- or violet-skinned humanoids. |
| Bailies | Cleopatra 2525 | Machine race that conquered Earth |
| Bajoran | Star Trek | Humanoid |
| Ba'ku | Star Trek | |
| Baliflids | Ascendancy | |
| Ballchinnian | Men in Black II | |
| Balmarian | Super Robot Wars | |
| Baltan | Ultraman | Space ninja |
| Bane | The Sarah Jane Adventures | Large tentacled aliens |
| Bandersnatchi | Larry Niven's Known Space | Artificially engineered single-celled gastropod, twice the size of a brontosaurus. Slaver's meat animal, sentient. Agree to be hunted for sport in exchange for currency to purchase mechanical arms. Asexual reproduction, impervious to genetic degradation or mutation. |
| Bandi | Star Trek | Humanoid |
| Banik | Farscape | Humanoid |
| Bannermen | Doctor Who | Humanoid |
| Bantha | Star Wars | Huge hairy beasts of burden |
| Barkonides | Perry Rhodan | |
| Barzans | Star Trek | |
| Battle Cupcakes | Bravest Warriors | The Battle Cupcakes were engineered by Danny to fight to the complete and utter death. |
| Baufrin | Renegade Legion | Insectoid centauroid |
| Batarian | Mass Effect | Four-eyed pirates |
| Beffel | Harry Turtledove's Worldwar series | A domestic animal native to Home, kept as pets by the Race. Befflem (plural) are described as having armored hides and possessing stumpy legs despite their agility. They are generally playful and agreeable and make an endearing squeaking noise, but their aggressiveness should not be underestimated: When cornered by another animal, they do quite well for themselves in a fight. Threats include tsiongi and prey include domestic cats and dogs. On Home, there were regulations against letting unleashed befflem run free. On Tosev 3 (Earth), such regulations were uncommon as befflem were much more inclined to do what they wanted than what the Race wanted them to do. They would adapt well on Earth, making many smaller native animals its prey. They also treated human masters the same as any of the Race. |
| Beings of the Extra Terrestrial origin which is Adversary of human race | Muv-Luv | |
| Benjari | Battlelords of the 23rd Century | |
| Benzite | Star Trek | |
| Berellian | Star Trek | |
| Berserkers | Fred Saberhagen's Berserker series | |
| Berubelan | Anachronox | |
| Besalisk | Star Wars | Four arms |
| Betazoid | Star Trek | Empathic humanoids |
| Bgztl | DC Comics Legion of Super-Heroes | |
| Biters | Factorio | |
| Bioroids | Intense Stories | |
| Bith | Star Wars | |
| Bismollian | DC Comics' Legion of Super-Heroes | |
| Bjorn | Space Quest | |
| Black Arms | Shadow the Hedgehog | Humanoid |
| Black Cloud | Fred Hoyle | Interstellar dust cloud |
| Black Oil | The X-Files | |
| Blastaar | Marvel Comics | Native of the Negative Zone |
| Blathereen | Doctor Who | Raxacoricofallapatorian |
| Blisk | Destroy All Humans! 2 | Bipedal, armoured crustaceans with a hive mind and a dependence on radiation. Former natives of Mars. |
| Blobs | Invader Zim | |
| Boazanians | Voltes V | Horned humanoids, though Hornless variants also exist. Those with horns are considered the upper-class while those without them are considered slaves. |
| Bolian | Star Trek | Blue-skinned humanoids |
| Boolite | Farscape | Humanoid |
| Borg | Star Trek | A race of cybernetically enhanced life forms from the Delta Quadrant of the Milky Way Galaxy. Able to assimilate almost any life form into their collective hive-mind and able to adapt to all forms of offensive capability instantly. |
| Bothans | Star Wars | Humanoid |
| Bortronians | Ready Jet Go! | Human-like aliens that populate Bortron 7, which orbits around a red dwarf star called Bortron. They communicate using sound effects. |
| Braalians | DC Comics' Legion of Super-Heroes | |
| Bradicor | Schlock Mercenary | |
| Brain Dogs | Bravest Warriors | |
| Brainiac | Smallville | |
| Brains | The Adventures of Jimmy Neutron: Boy Genius ("Win, Lose and Kaboom") | |
| Brakiri | Babylon 5 | Primarily night dwellers |
| Breen | Star Trek | Humanoid |
| Brikar | Star Trek: New Frontier | |
| Briori | Star Trek | |
| Brood | Marvel Comics | |
| Brunnen G | LEXX | Humanoid |
| Brunali | Star Trek | |
| Brutes (Jiralhanae) | Halo | Pack mentality humanoids of great physical standing. Part of a larger group known as the "Covenant". Intensely loyal to their religious beliefs, intent on completely wiping out the human race. |
| Budong | Farscape | |
| Bug+BurpBall | Adventure Time: Fionna and Cake | |
| Buggers | Ender's Game series | A hive mind species resembling insects. Invaded Earth twice before being destroyed at their home world by Andrew 'Ender' Wiggin. |
| Bulrathi | Master of Orion | |
| Bunless People | Bravest Warriors | The Bunless people inhabit the planet Bunless 9 and have no buns. |
| Bugs from Klendathu | Starship Troopers | |
| Bynar | Star Trek |