One of the biggest and best arcs in Dragon Ball Z was the Android/Cell saga, both of which tied into Goku's past destruction of the Red Ribbon Army in the original Dragon Ball. Dr. Gero's new army of murderous Androids were some of the deadliest opponents that the Z Fighters had ever faced, with the elderly doctor even turning himself into an Android to become more powerful and exact his revenge.
Three of the toughest and strangest Androids in the franchise, however, never showed up in the anime series, only receiving the spotlight in an ultimately non-canon movie. Super Android 13! may not officially be in continuity with the manga or TV show, but its title villains share some interesting similarities with Gero's later creations.
Android 14 and Android 15
Androids 13, 14 and 15 were supposedly disposed of in the main continuity, but they each show up to face Goku and his friends in the Super Android 13! film. Each of them bears a design representing a somewhat stereotypical depiction of American ethnic groups, to varying degrees of offensiveness.
The two "underlings" are Android 14 and Android 15, who both bear the classic Red Ribbon Army logo. Android 14 resembles a burly Native American warrior with a long ponytail, whereas the shorter, purple-skinned Android 15 resembles a stereotypical African-American pimp or gangster. This was accentuated in the English dub, where he was given speech patterns further reflecting this characterization. Likewise, Android 14 was portrayed more as a stoic, taciturn fighter, with the dub having to actually give him more lines.
Toriyama has noted that the names of the two Androids were reversed, with 14 meant to be 15 and vice versa. They both possess the power to fly on their own without ki, as well as project volleys of energy blasts. They also have the power to protect themselves with force field barriers and have ultimate attacks in which they tackle or launch themselves at an opponent.
Android 13's first form is similar to that of a trucker, with the dub giving him the affectation of a "redneck." He is an incredibly powerful combatant, standing up to the likes of Super Saiyan Goku. 13 possesses many of the same powers and abilities as 14 and 15, but despite preceding them, he is far stronger than his successors.
His most powerful attack is the S.S. Deadly Bomber, which he claims is powerful enough to destroy half of the Earth. His best-known trait, however, is his ability to combine with these two immediate successors. After Androids 14 and 15 were destroyed, Android 13 absorbed some of their remaining parts and components into his own body. This turned him into the massive Super Android 13, whose white hair now turned bright red while his skin became dark blue. This form's frame is apparently made out of adamantine metal, which sounds highly similar to Marvel Comics' adamantium metal.
The form has been compared to the Perfect Form of Cell, who was a completely organic "Android" also created by Dr. Gero. Other similarities include that of Dragon Ball GT's Super Android 17, the combined form of the heroic Android 17 and his evil counterpart that had been created by Dr. Gero and Dr. Myuu. Only after Super Saiyan Goku absorbs the power of his own Spirit Bomb is he able to stand up to Android 13 in his final stage, promptly defeating him with one punch. Sadly the villain has never been brought into official canon, but his impressive feats in the titular movie have made him a mainstay in several of the Dragon Ball franchise's video games.