Ten Treasures that Offer Advancement

In the vein of Advancement that isn't leveling up, here are some items which are designed to feature as treasure in a standard dungeon, fortification, settlement, or company. Common to each of them is a way for an interested PC to develop in ways they may not have initially anticipated. Often this involves a quest or quest hook of some kind. Ideally you can tailor this to lead into the dungeons or regions you wanted to set your story in anyway.

1. The Hand of Ransem, a stone hand covered in a thin black glove. This hand contains 3 MD that can be used to cast the spells silence, teleport through shadows, and mutually charm spooky creatures. Both the wearer and the Hand (which is intelligent) can be cast these spells at will. The Hand will attempt to use these powers to get the character in touch with members of the thief anti-nobility and (using its knowledge of rogue-sign and its own dread reputation) set them on the path to recover three other artifacts from its original master: the Eye of Ransem, the Cup of Ransem, and the Stone of Flenilla.
2. The Staff of Swords, a thin staff of mopane wood with an insert at the top to fit a candle. Whenever the owner defeats a true warrior, write down that warrior's name. The owner gets +2 to a d20 roll to emulate that warrior each day, and may elect to get this bonus after learning the result of the roll. You can only get this bonus once per warrior per day.
3. Calling Song for Comets, a scroll describing how to call falling stars down to your location. This is explicitly dangerous, and the author recommends you ensure you are perfumed with incense and free of sin.
1. a giant lump of iron falls to the ground, leveling everything within a mile, sparing only its worshipers and those with a notable magnetic field around them.
2. a floating island is pulled to the ground; it is covered in ancient ruins. Grab a medium-sized dungeon from your binder.
3. a lichjammer is pulled to the ground; a confused lich, flesh golem, and skull serpent look around confused.
4. the angel Perturabiel comes to you. He has little patience for those less pure than a saint, but seeks to do good.
5. a liquid rock the size of your fist floats down to greet you. It is as intelligent as a Very Good Dog and has the personality of a loyal goose.
6. a UFO lands nearby. The author of this scroll and all their friends wave from the window.
4. St. Julaman's Maul, a mace with seven empty facets running along the handle. Anyone holding it can detect if someone is remarkably guilty of one of seven sins. Killing such a person with the Maul sets a new gem in one of the facets and gives a new power. Once you've killed seven such people, the facets empty again, you can use the powers without holding the mace, and you become a Saint yourself, whatever that means in your setting.
1. Wrath - ruby - Give off fiery light. Deal +1d4 damage.
2. Sloth - amber - enter a trance for a set period, during which nothing can harm you.
3. Gluttony - turquoise - Eat a second lunch a day to heal 1d6+level HP.
4. Greed - jade - track anyone who has something you gave them, or something that comes from a hoard you inspect.
5. Envy - emerald - become unrecognizable at will.
6. Pride - opal - Anyone who listens to you is immune to the sunken cost fallacy, even when considering their own life direction.
7. Lust - amethyst - if charmed or enchanted, ignore the effect every other round.
5. The Dream of Age, a book describing a saga in which a major character summons their own infant self from the past and gives it up to a "Wild Lord," Canyieron. The ritual to summon your past self and to summon the Wild Lord are both described, and if you follow in the character's footsteps you immediately gain a template of an appropriate class and cannot advance in any other until your service ends. Bonus points if the last level of that class kills you.
6. Calumna's Cup, a silver hobgoblet. When two people drink from this cup, they switch bodies and the cup is teleported Somewhere Else. This effect is permanent unless they both drink from the cup again or are both are present for a remove curse spell.
7. Gigre of the Moral Frame, a recipe for a drug which is said to be able to remove unfavorable aspects of a personality, guiding them either to evil or good. If you create the gigre according to the recipe, roll a d4, with a penalty of 1 if you are unfamiliar with drugs and alchemy and a bonus of 1 if you are fully trained.
1. Exact opposite of intended alignment or personality change.
2. Entire person splits into two mostly identical people with exact opposite personalities. They are natural enemies but will not try to kill each other until all other options have been exhausted.
3. Personality splits into two, trading off control of the same body, Jekyll and Hyde Style.
4. Intended alignment or personality change.
8. Hadriana's True Process for Creating a Chemic Man, a set of fourteen stone tablets describing how to create a form of homunculus. It requires flesh from a creature it is shaped to resemble, which confers its templates and/or HD. It requires a three-word set of values to be scratched into its skull with a diamond-tip. It requires the sacrifice of a loving relationship. Other than these, the ingredients are not expensive. You can create powerful followers by these means.
9. The Elixir of Zoë, a potion said to be brewed by the daughter of King Midas. By swallowing a rose petal soaked in this elixir, you become immune to harmful transformations. This also makes the gold-themed tomb of Midas a cakewalk. Unfortunately, it also makes you the eternal enemy of the reaper king Lityerses.
10. Hurward's Brew, a recipe for a simple but tasty beer. Spend a month of downtime brewing and for the next month of adventuring you roll with advantage when recovering hit points from taking lunch.