The Red Drawf Crew

Dave Lister (Craig Charles) is the last human alive and the scum of the universe, he was discovered in a cardboard box beneath a grav-pool table. At the tender age of six his step father passed away, naturally he was too young to understand what was going on and was told that his father had gone to the same place as his goldfish. Consequently he spent many hours of his young life with his head down the toilet  reading the football results.

The Cat (Danny John - Jules) is decended from the domestic cat, during the cat wars two factions fought over whether the holy hat should be red or blue. (It should have been green) Only the sick or the lamb remained on board Red Dwarf, parented by a cripple and an idiot the cat is anything but a genious.
Felis sapiens resemble humans but can be distinguished by their teeth and six nipples,
The cat is a Narcissistic personified, he oozes cool and is always the height of fashion.

Arnold Judas Rimmer (Chris Barrie) having died during the Cadmium 2 radiation leak that killed the entire Red Dwarf crew (except Lister) Rimmer is resurrected as a hologram by the ships computer to help keep Lister sane, having been his room mate and number one source of hate in life Rimmer turns out to be the best choice.
Not bad for a senile computer, or was it luck?

Kryten 2X4B 523P (Robert Llewellyn) series 4000 mechanoid named android of the year 5 years running, duties including cooking, cleaning and general dogs body. (until he learns how to lie)
Helped by Lister to lie by watching films such as rebel without a cause, easy rider and Casablanca, Kryten can now accept the concept that there is no silicon heaven but only by lying.

Kristine Kochanski (Chloe Annett) Dave Listers long dead one time love interest, (this Kris is from an alternative dimension, of course) is intelligent, bright and witty; not the most likly candidate for joining this dimensions Red Dwarf crew.
As they say, beggars can't be choosers when your stuck in the wrong dimension.

Skutters.
Red Dwarfs rebellious service droids, a quirk in their design has allowed them to perform rude gestures, often demonstrated to Rimmer.