The Last Man on Earth
Stories that feature the main character as the last living human being on Earth in total isolation from any other sentient beings (terrestrial of extraterrestrial in origin, organic or artificial in sentience.) These stories can either feature a plot where everyone dies or disappears around the main character or where the mechanism of the death/disappearance of every one else sets the plot in motion.
The Last Woman on Earth
A rare gender reversal of the basic Last Man theme.
The Last Man on Earth (for now)
Many of these begin by suggesting the character is the Last Man, but other people (mainly fellow survivors) gradual appear or are encountered. Many feature periods of isolation broken by contact. Since this is the form that most Last Man stories take, the period of time before the main character meets other survivors is a distinguishing feature.
This has the further sub-types:
The Last Heterosexual Couple on Earth
The basic science fiction Adam and Eve story. They are depressingly common; sometimes referred to as “Shaggy God” stories. The more facile form results in the story being set thousand of years ago and the plot reveals the couple as being the Biblical Adam and Eve, asserting the literal truth of Genesis. They can also come in the form of a story set in the future, were the two must re-populate the Earth with no apparent concept of inbreeding.
The Last Love Triangle on Earth
The conflict of the love triangle can range from an unspoken attraction all the way up to pitched battle in the empty streets. A surprising number of these stories have been created.
The Last Groups on Earth
Instead of the Last Man encountering just a few survivors, enough come together to (or attempt to at least) restart a society.
There are also stories that do not feature the (overwhelmingly temporary) total isolation and the primal scene of the Last Man trope of travel or investigation of the de-populated world. The “Last Men” of these stories do not think at any point they are the last senitent being on the earth.
The Last (Hu)man on Earth
Last Man stories in that the world is de-populated of human beings but not of other sentient entities (intelligent animals, zombies, mutants, artificial intelligences.)
The Last Male on Earth / The Last Female on Earth
Another ironic take on the notion of the Last Man, where a male main character is/becomes or a female main character discovers/creates the only male in a world populated only with females. The story reversed in gender is quite rare. Stories of this nature often grapple with the theme of gendercide.
The Last (Fertile) Man on Earth
Stories where all men are impotent/sterile save one.
The Last MAN on Earth
An odd sub-set that should not be considered Last Man stories at all. The emphasis of the title is on the masculinity of the main character and not the de-population of Earth. Connotations with the Nietzschean conception of the Last Man are often present as well as a sub-text of anti-feminism or, at least, pro-masculinity. The main character is the last potent man on Earth, however the story chooses to define that term.