Below characters are those who are dead according to the site canon and under no circumstances can be played by any member.

Tom Morvolo Riddle aka Lord Voldemort - Killed by Albus Dumbledore

Alastor Moody - Death eaters
Barty Crouch Sr. -by Barty Crouch Jr.
Bathilda Bagshot - by Nagini
Bellatrix Lestrange - by Andromeda and Narcissa
Benjy Fenwick - by death eaters
Bertha Jorkins - by Voldemort
Broderick Bode - by Devils Snare
Cedric Diggory - by Peter Pettigrew
Charity Burbage - by Voldemort
Cornelius Fudge - by death eaters
Dobby - by Bellatrix Lestrange in the battle
Dorcas Meadowes - by Voldemort
Edgar Bones and family - by death eaters
Emmeline Vance - by death eaters
Evan Rosier - by Alastor Moody
Fabion Prewett - by death eaters including Antonin Dolohov
Florean Fortescue - by death eaters
Gellert Grindelwald - by Voldemort
Gideon Prewett - by death eaters including Antonin Dolohov
Gregorovitch -by Voldemort
Igor Karkaroff - by death eaters
James Potter - by Voldemort
Lily Potter - by Voldemort
Lucius Malfoy - died by passing through the veil of death
Marlene McKinnon and family - by death eaters
Moaning Myrtle - by Basilisk
Pandora Lovegood - in a charms accident
Peter Pettigrew - by Voldemort
Percy Weasley - by an explosion
Pomona Sprout - death eaters
Quirinus Quirrell - by Harry's Love
Rabastan Lestrange - by Sirius Black
Rodolphus Lestrange - by Remus Lupin
Regulus Black - by inferi
Severus Snape - by Rabastan Lestrange
Wilkes - by aurors