A glistening, squamous opportunity squats before you in the Bundle of Nerves +3, wherein you may snatch up the Lovecraftian horror of Silent Legions at a drastic discount. For only $9.95, you can get this undulating mass of modern OSR horror gaming and GM tools, with Sine Nomine-style implements for building your own primordial gods, nameless cults, ineffable horrors, and sandbox investigative adventures for fleshing out the non-Euclidian domains you might create. While Silent Legions is a complete game that's fully compatible with my Stars Without Number, the tools in this book are system-neutral and work handsomely with your nightmarish game of choice.
Not only that, but this trifling price gets you a PDF of the sterling Savage Worlds Deluxe plus its 166-page Horror Companion. And for those who care to part with a little more, you can have the dark promise of Accursed, Rippers 1e and its Companion, and the luxuriantly-illustrated dark-Celtic oppression of the Shadows of Esteren Prologue + Universe.
And I promptly clicked on this link to buy it. What's not to love here? Even if I do have one or two books, the bundle is well worth its price.
(No, I'm not affiliated with them. I'm just saying it's a good bargain.)