The Zords are often in the shape of animals - sometimes living creatures, sometimes dinosaurs and sometimes mythical beings - as well as vehicles. When the individual Zords are inadequate for the task, they can join together into a more powerful, humanoid robot called a Megazord.
Often, the sixth Ranger has a Zord that becomes its own Megazord. Examples include the White Tigerzord, Pyramidus, the Warrior Wheel, the Robo Racer, the Mega Winger, the Defender Torozord, the Max Solarzord, the Q-Rex, the Predazord, the Samurai Star, the Dino Stegazord, the Mezdon Megazord, the Delta Command Megazord, Omegamax Megazord, the Solar Streak Megazord and the Flashpoint Megazord.
Every season of Power Rangers from Mighty Morphin Power Rangers onwards saw a new set of Zords being deployed by the current Power Rangers. Each set is based on the Mecha from the connected Super Sentai series. This change of Zords occurred even before the yearly costume change to match the equivalent Super Sentai series.
The Zords used in Mighty Morphin Power Rangers are based on several subjects. The Dinozords are prehistoric creatures, the Thunderzords are mythical beasts, and the Ninjazords and Shogunzords are based on various ninja-related animals. All of them were created by the sage warrior Ninjor, though this was only revealed in the third season. The real reason behind the multiple themes of Zords is because three different Super Sentai series were used as the Zord fighting footage for each season. These series are Zyuranger, Dairanger, and Kakuranger.
In Mighty Morphin Alien Rangers, the Alien Rangers of Aquitar bring their own Zords to help them battle evil. These Battle Borgs very much resemble the Shogunzords (and may have helped inspire the Shogunzords construction, or vice versa), however rather than being piloted, they are controlled by telepathy. The Battle Borgs, when activated, copy any movement performed by the Aquitian Rangers. Throughout Mighty Morphin' Alien Rangers, the Battle Borgs were never made into a Megazord.
The Zeozords of Power Rangers: Zeo were created and controlled by the Zeo Sub-Crystals and Super Zeo Gems, as well as by the Gold Ranger of Triforia. The first set of Zords are based on mythological creatures or objects. The Red Ranger also receives his own humanoid zord. The Gold Ranger has a giant pyramid Zord, and gives the other Rangers smaller humanoid Zords as well as a quarterback-like humanoid wheel Zord.
The Turbozords of Power Rangers: Turbo are a collection of giant cars and trucks built on Earth. These are the first set of Zords created by the Rangers themselves. Also present are two sentient automobiles, Storm Blaster and Lightning Cruiser. Later in the season, the Rangers receive new Zords from the Phantom Ranger (a fire truck, an ambulance, a dumptruck, a police car, and a racecar/scooper).
The "Zords" of Power Rangers: Lost Galaxy are in fact sentient creatures called Galactabeasts, the first living Zords (this had happened in Zyuranger, Dairanger, and Kakuranger, but it had never happened in Power Rangers before).
The Zords of Power Rangers: Lightspeed Rescue are colossal machines (initially emergency vehicles) constructed by Operation Lightspeed and maintained by Angela Fairweather, then piloted by the Lightspeed Rescue Rangers.
The Zords of Power Rangers: Time Force are highly advanced machines sent from the future that the Time Force Rangers can pilot.
The Wild Zords of Power Rangers: Wild Force are living creatures of Animaria which share a bond with a Power Ranger. These can be summoned through the use of special orbs, the Power Rangers' Crystal Sabers, and the Lunar Wolf Ranger's Lunar Cue. Although each Ranger has his or her own set of orbs, it is not uncommon for them to share these orbs among each other. Should a Wild Zord die, its orb would instantly shatter, and the Ranger bearer would lose his/her powers if his/her powers were given by that particular Zord.
The Zords of Power Rangers: Ninja Storm, like the similarly-titled Ninja Zords of Mighty Morphin Power Rangers, are giant mechanical animals, piloted by the Power Rangers. They were maintained, at least originally, by Cameron Watanabe, and then by his virtual duplicate, Cyber Cam.
The Thunder Zords, similarly named to the zords of season two of Mighty Morphin Power Rangers, are a cross between insects and assault vehicles.
The Green Samurai Ranger's Samurai Star Chopper/Megazord is based on a helicopter, though it does have a decal on the front, bearing resemblance to a bird's eyes and beak.
The Bio-Zords of Power Rangers: Dino Thunder are dinosaur-like robots, created by Tommy Oliver and Anton Mercer during their collaboration. During the run of the show the name Bio-Zords was not used and was just replaced by Dinozords, also a name given for the first zords in Mighty Morphin Power Rangers. They are mostly maintained by Tommy's friend Hayley.
The Zords of Power Rangers: S.P.D. are law-enforcement vehicles in use by the Space Patrol Delta and its allies.
The Zords of Power Rangers: Mystic Force are mostly magical entities. However, the Zords of the core Ranger team are actually the Rangers themselves, who magically transform into forms called the Mystic Titans. The White Mystic Ranger does not have a Mystic Titan form, but instead grows to the size of the Mystic Titans. The Solaris Knight is the only Ranger who actually pilots a Zord, a six-part train called Solar Streak that transforms into the Solar Streak Megazord. Koragg the Knight Wolf also happens to control Catastros, a living horse Zord that can combine with himself. The Red Mystic Ranger also has control of Brightstar, a Unicorn-like Zord that, like Catastros, can combine with himself. There is also a Legend Mode for the Rangers in which they can convert into Mystic Legends, Mystic Firebird - the Red Ranger, and the other four Rangers combine to form the Mystic Lion. They form the Manticore Megazord.
The Zords used in Power Rangers: Operation Overdrive are called the DriveMax Zords and are all based on real world vehicles. There are eighteen DriveMax Zords used among six Rangers, exactly three Zords for each Ranger. The initial zords (1-5) become a core Megazord for the team, known as the DriveMax Megazord, which can combine with the five auxiliary Zords (6-10) to become various other forms, as well as two more powerful Megazords. There is also a Megazord formed from only the five auxiliary Zords, one Megazord for the sixth Ranger (11-13), and a taller Megazord that transforms from an amphibious aircraft carrier made up of five other Zords (14-18).
The Zords used in Power Rangers: Jungle Fury are the Animal Spirits which the Rangers possess within themselves.
The first instance of this occurring was during the first season of Mighty Morphin Power Rangers, in the Green With Evil arc, in which the Rangers first fought the evil Green Ranger and his Dragonzord. In this first instance, the Zord (and the Ranger) was soon turned to the side of good - although the Dragonzord would later be used for evil again, by Goldar and by the clone of the Green Ranger. The same idea was reused at the 'culmination' of the first season of Mighty Morphin, when Goldar piloted the Zord Cyclopsis against the Rangers. Lord Zedd also piloted a Zord called Serpentera, which was hugely powerful but never able to defeat the Rangers because it was continually running out of fuel. Serpentera reappeared in the Red Ranger team-up episode, Forever Red where it was finally destroyed by the Red Wild Force Ranger.
The idea of "evil Zords" was reused several times in later seasons, for example Power Rangers: Turbo, in which Divatox and her minions pilot several machines called DivaZords, and Power Rangers in Space, in which Psycho Yellow takes control of the Mega Voyager while the Rangers are in it.
In Power Rangers: Time Force there are several giant robots that are used by Frax and are not addressed as Zords, although in Mirai Sentai Timeranger (the Sentai Show that Power Rangers: Time Force came from) one of the giant robots was named the G-Zord. This was the first and only time that the Zord term was ever used on a Sentai Program. The G-Zord was adapted into the Dragontron robot when the footage was used on Power Rangers: Time Force.
In Power Rangers: S.P.D., a large assortment of giant robots are used by the monsters of the series. While not referred to as Zords, these robots are Zord-like in operation.
In Power Rangers: Operation Overdrive Moltor and Flurious had some robots in addition to their monsters while the Fearcats use a small assortment of giant robots similar to the monsters of Power Rangers S.P.D. While not referred to as Zords, these robots are Zord-like in operation.
There is one villain Zord in the US version which wasn't really a giant robot in the Sentai version. The one made-up Zord is the Zord Lothor piloted at the end of Power Rangers: Ninja Storm. This was done in order to use the final battle footage from Ninpuu Sentai Hurricaneger, the Sentai series that Ninja Storm is based on, since Lothor is an American-made Power Ranger villain.