For my kickstarter, I put together a 64-page, edition-neutral book of adventures, rules, idea germs, settings, races, and high-level options from my home campaign. I've turned it into a lulu book, which you can buy for $9.95.
I've featured a couple of pages from this book before. Here's a page from the book:
Rules for picaresque games
And here's another excerpt I haven't shown before:
THE FAIRY LAND’S DECAYING TREASURES
The feywild is a land of hyper-adventure, and you should be able to describe fairy-tale treasures, like trees that grow rubies as fruit, a beach covered with emeralds, or a coach carved from a single diamond. Problem is, for some crazy reason, DMs never want the PCs to get their hands on so much cash all at once.
Forget that impulse. You can't be stingy in the realms of wonder. ALWAYS GIVE OUT TEN TIMES THE USUAL TREASURE IN THE FEYWILD.
Feywild gems and jewels are different from natural-world treasure. When you return home with your basket of fey riches, you may find that your pearls have turned to eggs, sapphires to cupfuls of water, diamonds to ice, rubies to rose petals, and emeralds to leaves. If you're lucky, you may find a scattering of real gems in the bottom of your basket.
When any piece of Feywild riches is first exposed to the natural world's sun, or touched to iron, roll a d10. On a 10, the treasure keeps its form. Otherwise, it turns to some natural, worthless object. Roll individually for each major object; for collections, assume 10% of the items survived. Once a fey treasure has survived once, it is forever a permanent, real treasure.
Magic items are immune to this effect. But you could consider giving fairie-made weapons and armor a higher enhancement bonus that's only active in the Feywild. Once exposed to natural-world sunlight, +2 fey weapons become +1 sunrusted weapons.
In fairyland, there is no way to distinguish the "real" from the "false" treasure. The fey realm is made up of so much fantasy and glamor that the distinction is considered meaningless. Many fey treasures are enchanted by fairy craftsmen who think that flowers and leaves are as good origins for beautiful gems as dirty dwarven mines. Therefore, raw materials, like gold and gems, are more common and less valuable in the Feywild. Treasures are valued for the skill and beauty with which they are carved or engraved. Coins are rare: jewelry and luxury items are more often exchanged.
The nature of a precious item's creator can often be determined by the ingredients used to make it: a good fey creature might create gold coins from dandelions, and an evil one might use living poisonous beetles.
Because the feywild is so rich, its rare money transactions are conducted at prices inflated by 10x. The most common forms of fairy currency, though, are favors and promises.
For Fourth Edition players, here's a ritual that lets the PCs create fabulous fey treasures:
RITUAL: FEY CREATION
The caster makes an arcana check: a result of 15 means that the caster can create nonmagical gems, jewelry, or precious metal objects of up to 10 GP in value. For every 5 points by which the caster's check exceeds the DC, multiply the maximum GP value by 10. Thus, an arcana check of 35 means that the
caster can create up to 100,000 GP in value.
The ingredients for the ritual include natural objects to represent each item to be created (a bushel of pebbles to become silver pieces, a giant fey buttercup to become a golden goblet).
Special materials, like mithral, cannot be created with this spell. Items created with this spell cannot be turned into magic items. The casting cost for the ritual is arcane ingredients worth 1/10 of the value of the items to be created. This ritual may only be cast in the feywild.