The treasures mentioned thus far are all monetary. Their usefulness is immediate and obvious. They give characters wealth, and with wealth comes power and influence. However, there are other treasures, very desirable ones, that your characters will not want to sell or give away. These are the magical items that your characters find and use.
Although priests and wizards can make magical items (according to the guidelines your DM has for magical research), it is far more common for characters to find these items during the course of adventures. Magical items are powerful aids for characters. With them, characters can gain bonuses in combat, cast spells with the mere utterance of a word, withstand the fiercest fire, and perform feats impossible by any other known means. Not all magical items are beneficial, however. Some are cursed, the result of faulty magical construction or, very rarely, the deliberate handiwork of some truly mad or evil wizard.
A very few magical items are artifacts—items created by beings more powerful than the greatest player characters. These are perilously dangerous items to use. There are only three methods to determine how to use artifacts—dumb luck, trial and error, and diligent research.
There are many different magical items your character can find, but they all fall into a few basic categories. Each type of magical item has properties you should be aware of.
Magical Weapons: There can be a magical version of nearly any type of normal weapon, although there are admittedly few magical bardiches or guisarme-voulges. By far the most common magical weapons are swords and daggers. A magical weapon typically gives a +1 or greater bonus to attack rolls, increasing a character's chance to hit and cause damage. Perhaps magical swords are quicker on the attack, or maybe they're sharper than normal steel—the explanation can be whatever the DM desires. Whatever the reason, magical weapons give results far beyond those of even the finest-crafted nonmagical blade.
A rare few weapons have even greater powers. These may allow your character to sense danger, heal wounds, float in midair, or have the most amazing luck. The rarest of the rare can actually communicate with your character and are imbued with an otherworldly intelligence. While the most powerful of magical weapons, these clever instruments of destruction sometimes seek to impose their wills on their owners.
When you find a magical weapon, more than likely you do not know its properties. Some functions, such as the advantage it gives you in combat, can be learned by trial and error. Other properties must be learned through research and spells. Ancient histories and legend lore spells can provide information on the properties of your weapon. On rare occasions, properties are discovered through blind luck. Simply commanding the weapon to activate one power after another (hoping it will suddenly spring to life) works only for the most minor abilities—detecting danger, spotting secret doors, or locating treasure. Greater abilities require that specific commands be uttered, perhaps in long-forgotten languages.
Magical Armor: Enchanted armors are the complements to magical weapons. These armors have a +1 or better bonus to their normal Armor Class, being made of stuff stronger and finer than nonmagical armor. Furthermore, these armors grant some measure of protection against attacks that normal armors would not stop. Chain mail +1, for instance, improves the character's saving throw against the fiery breath of a dragon by 1, thus providing more than just a physical shield. In rare instances, armor may possess extraordinary powers. Although such armors are generally finely made and elaborately engraved. characters can discover the armors' powers only by the same methods they use to discover the powers of magical weapons.
Potions and Oils: Magical potions and oils are easily found but hard to identify. They come in small bottles, jugs, pots, or vials and clearly radiate magic if a detection spell is used. However, the effect of any potion is unknown until some brave soul tries a small sample. The results can be quite varied. The imbiber may discover he can float or fly, resist great heat or cold, heal grievous wounds, or fearlessly face the greatest dangers. He may also find himself hopelessly smitten by the first creature he sees or struck dead by a powerful poison. It is a risk that must be taken to learn the nature of the potion.
Scrolls: Scrolls are a convenience and luxury for spellcasters. By reading the incantation written on the pages, the priest or wizard can instantly cast that spell. He does not need to memorize it, have the material components handy, or do any of the things normal spellcasting requires. Experienced and powerful wizards normally spend their evenings preparing such scrolls for their own adventuring use.
Some scrolls are usable by all characters, granting special but temporary protections from various dangers—evil creatures, werewolves, powerful beings from other planes, etc. Other scrolls bear hideous or humorous curses, brought into effect at the mere reading of their titles. Unfortunately, the only way to know what a scroll contains is to silently scan its contents. For scrolls containing wizard spells, this requires the use of a read magic spell. Other scrolls can be read by all. This scan does not cast the spell written on the scroll, but it tells the character what is written there (and exposes him to the effects of curses). Once the scroll is read, it can be used at any time in the future by that character.
Rings: Magical rings are usable by many different classes and bestow a wide range of powers, from pyrotechnic displays to wishes. While the aura of a magical ring can be detected, its properties cannot be discovered until it is worn and the command word is uttered. (The command word is most commonly found inscribed on the inside of the band.) As with all magical items, some rings can harm your character. Worse still, cursed rings can be removed only with the aid of spells!
Wands, Staves, and Rods: These are among the most powerful of standard magical items. Wands are commonly used by wizards, allowing them to cast powerful spells with the flick of a wrist. Staves can be used by either a wizard or a priest. Staves can be truly destructive, dwarfing even the potential of a wand. Rods are the rarest of all, the accouterments of witch-kings and great lords. With rods come dominance and power.
Fortunately for your character, few of these items are cursed or dangerous to handle. But all must be operated by a command word—a specific word or phrase that triggers the power within. No wand, stave, or rod shows any indication of its powers by mere sight or handling. Careful research and probing are most often needed to tap the potential stored within.
Wands, staves, and rods are not limitless in their power. Each use drains them slightly, using up a charge. There is no power gauge or meter showing what is left. A character discovers his wand is drained only when it no longer functions or suddenly crumbles into useless dust.
Miscellaneous Magic: Miscellaneous magical items are where the true variety of magical treasures lies. Each item possesses some unique power. There are horseshoes to make your horse go faster, brooms to ride, sacks that hold more than they should, paints that create real things, girdles that grant great strength, caps to make your character smarter, books that increase ability scores, and much, much more. Each item is different and not all can be identified in the same way. The effects of some become obvious the instant the item is handled, donned, or opened. Others require research and questioning to learn the command word needed to activate them. All are quite valuable and rare.
Artifacts and Relics: Finally, there are artifacts and relics. Don't count on your PC ever finding one of these rarest of all magical items. Even if your character does find one, think carefully before you decide to let him keep it permanently. Artifacts are the most powerful magical items in the game. Indeed, many are powerful enough to alter the course of history! They are all unique and have unique histories. You can never find more than one Hand of Vecna in a world. Because it is so unique, each artifact has special and significant powers. Artifacts never appear by accident; they are always placed by the DM.
Finding artifacts is always the result of a very special adventure. Your DM has placed that artifact for a reason. It is not likely that he really intends for your characters to keep it. Instead, he has something arranged in which you need that artifact for a specific purpose. The problem with keeping artifacts is that they are too powerful. Not only do they unbalance your character in the short run, they also eventually corrupt and destroy him. The magical power of artifacts is such that they destroy their owners sooner or later. There is a price to be paid for power, and it is not a cheap one.
(See also Table 88: Magical Items in the Dungeon Master Guide and Magic Item Tables in the Tome of Magic)