Mortal Kombat has had its palette-swap ninjas with different elements ever since the beginning of times up until the rebootalicious MK9. Not all of the ninjas follow the most obvious line what comes to the element color consistency, however (which is good). It brings us the subject of the thread: Would have you made something differently? Should the green ninja focus in plants, the purple ninja in toxin or the blue ninja in aqua?
I liked the time when they were more technique-oriented like the female ninjas are; Scorpion had his teleport kick and Sub-Zero had the spine rip that had nothing to do with their actual elements. Now every special move involves an element, in a way or another. I guess it's the special effects.
There is a list of examples below that I quickly made including alternative elements and consequently different names. I included the ninjas seen in the games only – you can change their names how you see fit, tell what their "element" or focal point is and what would their color and looks be (Saurian, Enenra, souls etc.). Chameleon and Smoke have had more than just those colors listed though. To keep it simple, let's focus in the male ninjas for now. Now share us your thoughts and variations. Examples:

• Yellow fire ninja Scorpion ⇨ desert "Sandman"
• Yellow bomb ninja Cyrax ⇨ bacteria "Sikk LK-H1N1"
• Red missile ninja Sektor ⇨ flight "Starscream LK-TF1"
• Red telekinetic ninja Ermac ⇨ blood "First Aid Kid"
• Blue ice ninja Sub-Zero ⇨ water "Super Soaker"
• Green acid ninja Reptile ⇨ plant "Ivysaurian"
• Teal mime ninja Chameleon ⇨ dreams "Inception"
• Gray smoke ninja Smoke ⇨ metal "Megadeth"
• Purple storm ninja Rain ⇨ poison "Michaels"
• Black shadow ninja Noob Saibot ⇨ oil "Mexican Bayman"
• Orange snow[?] ninja Wu Lae ⇨ lava "Solar System"
• Brown quake ninja Tremor ⇨ wood "Pinocchio"

Notice: "Ninja" as in the NeRdS ́ sense – not as in "shinobi".