Worm

A worm was any manner of creature that tended to be round, long, and articulated.

Serpentine (higher) lifeforms

• Deathworms (DW: Doctor Who)
• Prisoner Zero (DW: The Eleventh Hour)
• Psychic Worms (BFA: The Wormery)
• The Process (NA: Cat's Cradle: Time's Crucible)
• Voracious Craws (NSA: Sick Building)
• Wurms (NSA: The Art of Destruction)
• Harmonelids (DWA: Earworm)
• Alvarian space wyrms (IDW: The Forgotten)

Lower lifeforms

• Earthworms
• Oroborous Worms (BNA: The Mary-Sue Extrusion)
• Jakra worms (NSA: Ghosts of India)
• Spulver Worms (EDA: Coldheart)
• Bore worms (TWN: The Undertaker's Gift)
• Alien tapeworms (TWN: Slow Decay)
• Myxilinic frost-worm (TDL: The Colour of Darkness)
• Thermortian Sand Worm (IDW: The Forgotten)
• Alifabe (DWA: Sky Scraper)
• Natrium Worm (DWA: The Salt Solution)
• Alvega Earthworm (TV21: The Amaryll Challenge)
• Norebo Worm (TN: Nightdreamers)
• Bookworms (IHP: Hunger from the Ends of Time)

Other creatures mistaken for worms:

• Giant maggot (DW: The Green Death)
• Cybermat (DW: Revenge of the Cybermen)
• Horda (DW: The Face of Evil)
• Fendahl (DW: Image of the Fendahl)

Other uses:

• Donna Noble compared Time Lords to worms after witnessing the severed hand of the Tenth Doctor grow into a new Doctor. (DW: Journey's End)
• Wormholes are unrelated except by name.