Suggestions by @mr_blue_sky

Howie Mandel

as Gizmo in If Scooby-Doo! had slasher icons

Henry Gibson

as Chop Top Sawyer in If Scooby-Doo! had slasher icons

Norman Alden

as Ghostface in If Scooby-Doo! had slasher icons

Bruce Campbell

as Ash Williams in If Scooby-Doo! had slasher icons

Cassandra Peterson

as Elvira in If Scooby-Doo! had slasher icons

George O'Hanlon

as Norman Bates in If Scooby-Doo! had slasher icons

Roddy McDowall

as Herbert West in If Scooby-Doo! had slasher icons

Michael Bell

as Freddy Krueger in If Scooby-Doo! had slasher icons

Don Adams

as Chucky in If Scooby-Doo! had slasher icons

Ted Cassidy

as Michael Myers in If Scooby-Doo! had slasher icons

Peter Cullen

as Killbots in If Scooby-Doo! had slasher icons

Don Messick

as Pennywise in If Scooby-Doo! had slasher icons

Vincent Price

as Pinhead in If Scooby-Doo! had slasher icons