These cards are double sided with the front and back being the same.
Credits: Phagophobic difficulty was created by Chris Jennings, all other cards were created by Jacob Busby, exception for the Lure of Corruption, whose provenance is unknown.
Divine Blessings and Hellish Curses
This is a single double-sided card. If an investigator receives a blessing when they already have one, they should take the Divine Blessing and place it adjacent to their current blessing. Likewise should any investigator receive a curse when they already have a curse, they should take the Hellish Curse and place it next to their investigator.
Credits: Michael Redston
Generic Plots can be used with any Ancient One which does not have plot cards of its own. Optionally you could replace the second Sinister Plot player by a standard Ancient One with a Generic Plot.
Black Epic Battle card
This card requires the Epic Battle rules. Should the Epic Battle occur, the players should form a deck composed of the black card (below), two red cards plus two red cards for every seal on the board, and two green cards plus two green cards for every seal on the board. This incentivises players to score as many seals as possible, even if they eventually plan on taking on the Ancient One in battle.
Black Goat of the Woods Variant
This variant makes the One of the Thousand cult a more beguiling addition to the game.
Arkham Horror Book Club
Arguably fiddly and only applying to some of the Tomes in the game, nevertheless, the Arkham Horror Book Club is an attempt to make Tomes more interesting than a mere skill check to acquire some spells.