Mark Harrigan, Unspeakable

This deck uses only the core sets and the Path to Carcosa. You should upgrade the Beat Cops first, First Aid, and put Ever Vigilant and then some Extra Ammunition. After that, I usually go for Stick to the Plan since it thins out Mark's deck and guarantees you can get an Emergency Cache out early. The other big gun out there is the Shotgun, but I don't think it's viable without Custom Ammunition or Act of Desperation to get more ammunition.