There is no shortage of Halloween themed tv episodes or lists of these episodes, but we decided to make a short list from shows of varying genres that are favorites. Not all of these are Halloween episodes specifically, but instead have creepy/spooky/costumey elements.
Bones “Mummy in the Maze” (3x05)
Boy Meets World - “And Then There Was Shawn” (5x17)
Buffy the Vampire Slayer - "Fear, Itself” (4x04)
Community - "Epidemiology" (2x06)
Dawson's Creek “Four Scary Stories” (5x09)
Psych* - “Tuesday the 17th” (3x15)
Psych - “Heeeeere’s Lassie” (6x11)
Smallville “Wither” (6x03)
The Vampire Diaries “Haunted” (1x07)
The X-Files - “Home” (4x02)
*I actually reccommend every Psych Halloween episode and here's a list of those.