Im working scribe (just hit 75.0) and placed all types of slayer books on a new vendor called Crispy Caster (used to be the wand vendor) at the Cliffside Emporium in Mag, top NE side of the Island, AKA Molly's house. I currently have stocked Blood, Poison, Air, Earth, and Troll/Oger slayers on the top level of the pack. Due to most peoples desires to get the new uber Shame loot with ease these are very pricey. These also work with Myst skill by giving 3X damage to directly applied damage spells (a rising Collosus doesn't do 3X damage but Bombard does, for example). As soon as my skill allows, I'll try to stock Super Slayers... but since this is soooo boring I wouldn't expect any.