Sailor Moon Special Powers and Items

Sailor Moon's pre-battle taunt pose, an iconic symbol throughout the series:
"In the name of the moon, I shall punish you!"

Usagi is not shown using any special powers in her civilian form. She must first transform into a Sailor Senshi by wearing a special device (usually a brooch) and shouting a special command, which activates the device. Her original transformation command is "Moon Prism Power, Make-up!" She gains a new basic transformation sequence for each of the five major story arcs. In her basic form, the command changes as she becomes more powerful and obtains new transformation devices, evoking "Moon Crystal Power" and later "Moon Cosmic Power". A transformation into Super Sailor Moon initially requires her to already be in Senshi form and to use an additional item (called the Holy Chalice/Rainbow Moon Cálice) as well as the command "Crisis, make-up!", but in the anime this saps her strength. For the fourth story-arc she gains the ability to transform directly into Super Sailor Moon via Moon Crisis, and in the fifth arc becomes Eternal Sailor Moon with Silver Moon Crystal Power in the manga, or Moon Eternal in the anime (and once in the manga). At first, she is required to be in her Super Sailor Moon form, in the anime, to become Eternal Sailor Moon, as the upgrade to her Brooch is temporary. When facing off with Nehelleina for the final time, the Brooch is permanently upgraded allowing her to become Eternal Sailor Moon directly.
Most of Sailor Moon's anime transformations involve the use of shiny red or pink ribbons which fly out of her brooch and form her uniform. Feathers and wings also figure prominently in some sequences, particularly the transformation into Eternal Sailor Moon. When she de-transforms, the ribbons reappear and unravel from around her body and go back into the brooch. Usually the clothes she was wearing before she transformed reappear, but if her de-transformation is forced, she may be left naked with the ribbons hanging loose around her body. She also has the Disguise Pen, which allows her to take on a human disguise by saying "Moon Power!" This is used very frequently in the first story arc, but is only mentioned once during the third arc.
As the protagonist and leader, Sailor Moon has the most special powers of any character in the series. Her physical attacks, usually one-offs and not always successful, include Sailor Moon Kick and Sailor Body Attack, as well as the occasional use of her hair pins as projectile weapons. In her very first battle, she cries in terror and the red hair pieces on her odango amplify the sound waves, doing damage to the enemy. Her odango ornaments can also be used to hear faraway sounds, although this is rarely ever used.
General magic attacks are her most common type of power. In each adaptation of the series she can remove her tiara and turn it into a throwing weapon, which is her first major attack and which she continues to use on occasion far into the anime series. In the anime she demonstrates the ability to control the path of her Tiara, and once, to enlarge it and then shrink it around the enemy, ensnaring them. In the manga, a powered-up tiara enables her to attack with Moon Twilight Flash while in the live-action series this move requires an item called the Moon Stick and is her primary attack, though she also sometimes uses unnamed beam attacks. In the manga and anime she only uses the Moon Stick to perform Moon Healing Escalation and return possessed humans to their normal selves; Luna says in the anime that this item belongs to the leader of the Sailor Senshi. In the anime, she once uses her tiara to purify a group of possessed people, and in the live-action series she can heal others without any incantation.
One cannot always distinguish between healing or purifying powers and attacks, as the monsters of the day in the series are usually created by corruption of an object or person. Sailor Moon has one or two primary attacks per story arc, most of which require a unique rod or wand, and in the original anime, each of them causes the target monster to shout a phrase and revert back to what it was made from (or to dust). These primary attacks are: the first series' Moon Healing Escalation, the second series' Moon Princess Halation, the third series' Moon Spiral Heart Attack and Rainbow Moon Heart Ache, the fourth series' Moon Gorgeous Meditation, and the fifth series' Starlight Honeymoon Therapy Kiss and Silver Moon Crystal Power Kiss.
A handful of powers come up only once and in critical situations; often the common repeating powers in the anime are only one-offs in the manga. In the anime, Sailor Moon uses her transformation command when battling Queen Metaria and when turning the Ayakashi Sisters into normal women. She says Moon Cosmic Power when struggling to destroy Pharaoh 90, and at the end of the series uses Silver Moon Crystal Eternal Power to fight Chaos.
Sailor Moon can be temporarily powered-up by the other Sailor Senshi lending her their powers, as shown in the climax of the Sailor Moon R movie and multiple times throughout the series. She also often attacks in tandem with her daughter, Sailor Chibi Moon, and, at critical moments, receives power from individuals such as Luna, Queen Serenity, her future self, Mamoru, ChibiChibi, and others.
By far, Sailor Moon's most important item is the Silver Crystal, which is the "holy stone" of the Silver Millennium. It figures significantly in the first, second, and fifth story arcs, as it is the proof of her identity as the Princess and the source of her power. It eventually evolves into the Silver Moon Crystal.
In terms of personal items, Sailor Moon attaches particular importance and sentimental value to her gold locket. In the anime it plays a version of "Moonlight Densetsu", the opening theme for the series. Sailor Moon finds it after it is dropped by Tuxudo Mask. It is a relic of their past lives which she had given to him as a gift. Sailor Moon uses this locket in moments of sadness caused by her separation from Mamoru.