SCROLLS
Aggravate monster: "High pitched humming noise", makes dormant monsters start moving. Be careful with this one.
Create monster: Creates a random monster near you.
Enchant armor: Improves your armor. "Your armor glows blue for a second."
Enchant weapon: Improves your weapon. "Your mace/dagger/other weapon glows blue for a second."
Hold monster: Makes the monsters in the room freeze.
Identify: Shows you what a certain type of item (red potion, scroll with "blorp esh mesa" on it, etc.) does. Once an item type is identified, the other items of the same type are automatically identified; for instance, if you identify a purple potion as levitation, all other purple potions will read "potion of levitation".
Magic mapping: Shows you a map of current level, even hidden areas.
Remove curse: Removes curses on cursed items (allowing you to remove them). "You feel like someone is watching over you."
Sleep: Makes you fall asleep for a few turns.
Teleportation: Teleports you to another place on the same floor.
RINGS
Add strength: Increases your strength by the amount said (+2 increases it by 2, -2 decreases it be 2, etc.) If the amount is negative, it is cursed, so watch out.
Adornment: Nothing. Wastes room for other rings. Cursed.
Aggravate monster: In effect, no monsters are dormant.
Searching: When you move, you automatically search the surrounding area.
See invisible: Possibly reveals traps or passages.
Slow digestion: Makes food last for more turns.
Stealth: Not sure, but it isn't cursed.
Sustain strength: Probably keeps you from losing strength.
Teleportation: Teleports you every few seconds. Cursed.
STAFFS/WANDS
Do nothing: Wastes time and does nothing.
Polymorph: Zap a monster with this, and POOF! it transforms into a different monster. Be careful- it can transform them into stronger ones as well!
TRAPS
Bear trap: Traps you for several turns.
Poison dart trap: Shoots poison darts at you, reduces HP.
Rust trap: Can reduce the effectiveness of your armor.
Sleeping gas trap: Makes you fall asleep.
Teleport trap: Teleports you to another room on the current level.
Trap door: Sends you to the next lowest level.