Normal
Normal ninjas are the first variation.
DX
DX (Dragon Extreme) is the second type of ninja. These ninjas wear dragon clothing. The dragons on their suits are all breathing different kinds of elements (Cole, dragon breathing rock; Zane, dragon breathing ice; Jay, dragon breathing lightning; Kai, dragon breathing fire). The ninjas in their DX attire also have gold and red spinners. Ninjas become DX rank once they tame their respective dragon. Strangely, though all DX ninjas are sold in a Spinner Battle Pack (except for Jay), no dragon was included.
Kendo
Kendo Ninjas are the third variation of the ninja. Kendo uniforms are the original ninja robes with new helmet pieces with chest armour. In Ninjago: Masters of Spinjitzu, the ninja use the Kendo armour for training, however in the sets, they are often seen in combat with the Serpentine.
ZX
ZX (Zen Extreme) is another type (the fourth) of ninja. These ninjas have shoulder pads that also include a round piece (representing a scabbard) to put Katanas in. They also include a different ninja mask that has a gold or silver visor. Lloyd Garmadon has a ZX variation to represent the Green Ninja.
NRG
NRG is the fifth type of the ninja. They are the ninjas in their true potential form. They appeared in summer 2012 spinners. In NRG form, ninjas are made of pure energy of their element. The emblems depict the symbol in the top left corner with the element coming from it in a vertical line, a horizontal line and a diagonal line. They look similar to the DX form. The first episode NRG appeared in was "Tick Tock" and the first ninja to use it was Zane. In the episode "Once Bitten, Twice Shy" Jay unlocked his full potential. In the episode "The Royal Blacksmiths" Cole unlocked his full potential. And in the episode "The Green Ninja" Kai unlocked his full potential.
Kimono
These Robes was first introduced with Lloyd in LEGO Ninjago: Character Encyclopedia. It was known in the book as another ZX robe but when they get their new suits in the episode Island of Darkness they get them in the Temple of Light when Kai, Zane, Jay, Cole get their elemental powers back and Lloyd gets the power of the golden dragon fighting style, only practised by The First Spinjitzu Master.