[] The Humors of Flesh, how to brew potions that heal the body and inflame the mind, potions to kill without a mark or in unspeakable pain, cordials to fortify one though the long journeys, incense that brings forgetfulness or nightmare (Roll 1d6 diplomacy and 1d6 intrigue)
This seems by far the most useful personally. Magic medicine in medieval Europe? Kings would stand in line for our attention.
I assume the ingredients wouldn't be something native to ME, cuz that would suck majorly.
[] Spells of Steel and Blood, how to forge hate into as sword and spite into an arrow, leaving the battle half won before it is begun (Roll 1d6 Martial and 1d6 Learning)
My personal favorite. I like me some martial characters and martial spell casters.
[] Gifts of Fire, how to unleash the wrath of flame and ruin from charcoal, sulfur and the leavings of man as well as how one might guard against it with high and cunning walls (Roll 1d6 Martial and 1d6 Stewardship)
Probably most useful for our future domain.
But we all know what we have to pick...
[X] Tablets of Song and Ruin, writ upon stone for no parchment could bear the weight of it, the deep wisdom to fear an echo of the world's song and by great effort of Fea change some small note of it. Power in its purest form and for men its most perilous(+1d6 to all stats; Dangerous to Use)
Having to find balance between hubris, arrogance and fear of failing would be absolutely amazing.