One I wish I could recall more about ( it was the 60's ) was a warlock who became a witness and was tormented by the demons until he proved he was not backing down.
I remember one like that, though I thought it was published around the '80s. A guy who used to summon demons who, after he started studying, had the demons clawing at his window trying to get at him. There's also a story in one publication about a woman who had snakes falling from the ceiling in her bedroom and filling up the entire room. I can't find either of those stories on the CD-ROM at the moment, though.