I am only covering those giant robots called 'zords' on Power Rangers.
Dora Talos / CyclopsisIn MMPR, it was Goldar's 'Warzord.' In Zyuranger, Dora Talos was a robot piloted by Bandora's son Kai and hypnotized children. Originally in "Doomsday Part 1 & 2," Rita was going to have a son named Bubba (Kai) and he was going to pilot it.
Daijinryuu / SerpenteraSerpentera was Lord Zedd's personal zord. Daijinryuu was no zord, it was a god, angry at the ruckus that the Dairanger and Gorma were making. Serpentera became the wedding carriage for Rita and Zedd. In Japan, this is the only one to get a toy. In America, it got a toy as well.
Land Zuzoon, Marine Zaboon, & Sky Gigune / DivazordsIn Turbo, Divatox had the Divazords - lion, shark, and eagle. In Carranger, they were issued by Exhaus. Land Zuzoon used its tractor beam to capture Dappu, drained Dappu of his Carmagic Power until being destroyed by Carrangers in their RV Twister Cutter attack on the head and legs, avoiding where Dappu was held in the waist.
Braking / Metallosaurus
Havoc's robot, Metallosaurus almost became a toy. For Carranger, Braking came to RichiRitchihiker in a vision. They both defeated the first batch of cars and was defeated by the new five vehicles.
Norishiron 12 / TerrorzordIn Carranger,
created from punch-out cardboard model by Grotch from a Space Land magazine brought by Exhaus. It accidentally reverted into carboard sheets from Chiipuri's youth cream. Porto built the Terrorzord and it was defeated when it was accidentally turned into a camel by one of Divatox's monsters. Elgar was on top of a camel.
G-Zord / DragontronFans make a big deal that this was first robot in Sentai ever to be called 'Zord.' A living battle robot that was lost in a time experiment. After breaking away from Ransik, Frax built his own powerful Zord called Dragontron. In both cases, the Red Ranger from the future came to take the space of the present Red Ranger.
NeoCrisis / Doomtron Gien and Frax's final robot, they had the same power source as V-Rex/Q-Rex, making vortexes in the sky. In Time Force, Ransik took it for himself, and made the enslaved Frax pilot the robot against the Rangers. Red blasted the Rex with its controler weapon, converting its blue crystal into a yellow one, giving it enough power to destroy the robot.
Megatagame / ZurganezordThey were both made and piloted by Sargain/Zurgane.
Megatagame II / Zurganezord IIThey were both made and piloted by Sargain/Zurgane. It both had a slim version.
Megatagame III / Zurganezord IIIThey were both made and piloted by Sargain/Zurgane. They both were used to take the information from the Karakuri Ball/Power Spheres.
GainGain / Hyper ZurganezordThe other form of the last robot, that came with its own sphere.
Megatagame-sexy / KaprizordBefore Sargain died, he left the others giant robots. This one was for Wendinu. Nanami punched the glass and painted Wendinu's face. In NS, Kapri got the zord and it was destroyed by the Hurricane Megazord and the Mighty Mammoth. Kapri and Marah got Shimazu to pilot one of 'their zords,' not saying it was Zurgane's.
Furabirobo / Marahzord
A re-colored model of Furabijenu, Furabijou piloted it, Sargain made it. Marah piloted it in NS.
Giant Musasabi / ShimazuzordA re-colored model of Musasabi, the original didn't appear in NS. Sargain made it for Satorkara. Kapri and Marah gave this robot to Shimazu.
Lothor's ZordThis wasn't even a zord, nor a robot in Hurricanger. It was the big boss Tao Zanto. The Lothorzord is destroyed, but in the process, its destruction takes out the Storm Megazord as well.
Replicant ZordMezadon made a copy of the Thundersaurus. It appeared briefly. This is an actual zord. It was called Blizzard Force Megazord in the toys and had different colors. It was originally called Bakureno in Abaranger.
ZelzordSame thing as Lothor's Zord, it wasn't a robot in Abaranger. it actually was their headquarters taken over by their boss. In Dino Thunder, it was called the Zelzord, Zeltrax's.
A-Squad's MegazordThis Zord (that went from flying drill to robot) was used by the SPD A-Squad Power Rangers when they kidnapped Cruger. Destroyed by the S.W.A.T. Megazord. All the robots used by the villains in SPD were not called 'zords.'
Moltor's Robot and Dragonizer could also be considered 'evil zords.'
LavadactylsThey were designed to resemble the dinozords from Dino Thunder and were piloted by Lava Lizards.
Many of the robots used by the Fearcats, Flurious and Moltor could also be considered evil zords in Operaiton overdrive.