Power Coins

The Power Coins are a set of magical coins forged by Ninjor that the Mighty Morphin Power Rangers used to morph.

Dinosaur Coins
The Dinosaur Coins were the first set of Power Coins that the Power Rangers used. These coins powers were based on ancient prehistoric animals and the first five had the image of the animal they represented engraved on them, the Mastodon, the Pterodactyl, the Triceratops, the Saber-Toothed Tiger, and the Tyrannosaurus. The sixth was based on the Dragon, but instead had a design based on the dragon's foot engraved on it. At some point, Zordon managed to gain the first five coins while Rita Repulsa got her hands on the Dragon Coin. The coins were combined with the rangers' Power Morphers, which would then allow them to morph. Zordon gave the coins in his possession to Zack Taylor, Kimberly Ann Hart, Billy Cranston, Trini Kwan, and Jason Lee Scott. The Dragon Coin was given by Rita Repulsa to Tommy Oliver after she turned him into the Green Ranger. After the Dragon Coin lost its powers, Zordon and Alpha created a new White Tiger Ranger whose powers came from the Tiger Coin. After Rito Revolto came to Earth and attacked with a band of monsters, he succeeded in overloading the Command Center, destroying the Power Coins. The Coins could also be used to emit magical charges which could re-energize Zordon.

Power Crystals
The Power Coins could also be transformed into the Power Crystals. To do so, a ranger would place his thumb and index finger at the edge of the coin with the head facing out, then elongate it into the crystal, down to the point. The Rangers would also shout "Two-One-Power-Up" and insert the Power Crystal into a slot on the helm of their Dinozord. When this was done, the rangers could fire an energy blast from each zord in the Megazord Tank Mode or one concentrated one in Battle Mode. Whenever one of the rangers were in trouble, the crystal could be used to transport the other to wherever they were. They could also be teleported through the Morphing Grid into the rangers' Power Weapon.

Ninja Coins
With the destruction of the Dinosaur Power Coins, the rangers were sent by Zordon to seek out Ninjor so as to get new ones. After proving themselves worthy, he gave them new Power Coins with Ninja Powers and the Ninjazords. As well as Power Ranger forms, these coins also gave the team Ninja Ranger forms, which allowed them to perform various ninja tricks, such as disappearing and super speed. However these coins were also destroyed after Master Vile turned back time with the Orb of Doom, turning the Power Rangers into children. Billy created a device that could turn them back to the proper ages, which used the Ninja Coins as its power source. Unfortunately only Billy was able to use it to turn back into his normal age, before Goldar and Rito stole them and Zedd and Rita destroyed them.

Alien Coins
The Alien Coins were used by the Aquitian Rangers, who were given them by Ninjor 1000 years ago. Unlike the rangers who used the Power Morphers with the coins, the Aquitian Rangers drew directly from them to morph.

Trivia

 * The Power Morphers and Coins used originally in the show were toy Dino Bucklers from Kyoryu Sentai Zyuranger, the Super Sentai series the first season of Power Rangers was based on. Using toys from Super Sentai as props would become a tradition in Power Rangers.