"NIGHTMARE" ALIENS

The "Nightmare" aliens are a humanoid species which had developed a space faring civilisation as of the 20th centuryé The have a large head with a brain-like relief over their ehads, large bulbous round eyes and long point ears. A scout from this civilisation came to Earth in 1982 to test the human race through one of its specimen. It boarded a submarine carrying a large nuclear arsenal and tried to fire it in order to cause an all-out nuclear war. Success in stopping him was to be the proof the aliens needed to let Earth be while failure meant the destruction of the humans by their own hands. Luckily, the bomb were detonated before reaching detonation and the alien destroyed.

Source: Voyage to the Bottom of the Sea, "Nightmare", directed by Charles Rondeau, written by Irwin Allen and Sidney Marshall.

DOG-FACED ALIENS

The Dog-faced Aliens are a sentient humanoid canine species which has developed an advanced civilisation and are known to use robot servants.

Source: Irwin Allen, Lost in Space. ("War of the Robots")

Note: The Dog Face aliens bear a strong resemblance to the Anticans of Star Trek: The Next Generation.

LOBSTER MAN

Planet of Origin: A water planet in the Milky Way,
The aliens known known as Lobster Men are sentient crustacean humanoids which develop an advanced civilisation capable of space travel. While roughly anthropoid in shape and possessing a face with disturbingly human features surrounded by a beardlike hair collar, the Lobster men are covered by chitin plates, have loster-like pincers instead of hands which are strong enough to cut through steal at the end of long arms as well as small lobster-like legs coming of their arms, legs and forehead. If those smaller limbs are functional has not been witnessed. They also possess lobster-like antennas.

The lobster man have been watching Earth for "as long as men have talked out loud" and are known to have sent an emissary to Earth as a scout for an invasion at the end of the 20th century. The scout tried to cause a nuclar explosion to wreak havok, an effort that was thrwarted by the crew of an american submarine.

Source: Voyage to the Bottom of the Sea, The Lobster Man, directed by Jus Aldiss, written by Al Gail and Irwin Allen.

The Lobster man's spaceship.

SATICONS

Saticons are a mysterious faceless humanoid entities of unknown origin. They travel in groups of three, wear long, black garments, and bowler hats. The lead Saticon had a sun-like icon on the front of his hat.
Saticons can travel from planet to planet by means yet unknown and have access to highly advanced technological knowledge. When seen, they always seem to be after an object of power with which they want to accomplish some terrible feat.
Source: Lost in Space (Wreck of the Robot, The Galaxy Gift)

BUBBLE CREATURES

The bubble creatures are a non-humanoid spacefaring species resembling a gnarled, melting lump of greenish-brown flesh, with several pulsating multi-faceted 'bubbles' of various colors protruding from various spots on their body. They communicate by electric arcing on the surface of their bubbles.
Source: Lost in Space "The Derelict", "Prisonners in space"

KEEMA

Keema are humanoid aliens who developped a spacefaring civilisation. Toward the end of the twentieth century, they were at war with the Zedams. Pink skinned, Keema have enormous heads and hands with the rest of their body of similar propotions to that of humans. Anatomically highly asymetrical, they appear subject to genetical malformations which are possibly side effects of the war they're engaged in. The only recorded contact of a Keema with mankind was with a family of space explorers stranded on an alien planet where the Keema leader was to meet the Zedam leader in a duel whose winner would win the war. From the sayings of the Keema leader, though, it was clear that he knew much about Earth's culture before meeting the explorers. Keema are able change their appearance but the nature of this ability is not known, although, as Zedams can do the same, it is probable that this is the result's of each culture mimicking the discoveries of the other to better thwart them.  
Source: Lost in Space, The Golden Man (The term Keema is used in the episode to designate the Keema leader. It might not be the species' real name).

ZEDAMS / ALFROIDS

Zedams, aslo known as Alfroids, are batracian humanoid aliens who developped a spacefaring civilisation. Toward the end of the twentieth century, they were at war with the Keema. Zedams have a huge froglike head, webbed hands and feet and are probably amphibious. They are known to wear long robes and jewelry.
The only recorded contact of a Zedam with mankind was with a family of space explorers stranded on an alien planet where the Zedam leader was to meet the Keema leader in a duel whose winner would win the war. From the sayings of the Zedam leader, though, it was clear that he knew much about Earth and had probably visited it.
Zedams are able change their appearance but the nature of this ability is not known, although, as Keema can do the same, it is probable that this is the result's of each culture mimicking the discoveries of the other to better thwart them. 
Zedams are known to use short range teleporter technology and spaceship mixing mechanical and vegetal elements.
Source: Lost in Space, The Golden Man (The term Zedam is used one time in the episode and its orthograph is approximative.) In "The Galaxy Gift", where the term Alfroids is first mentionned for the species name.

A Zedam one-man spaceship, note the mix of mechanical and vegetal parts.