The Android Saga introduces several new characters to Dragon Ball Z's story, including none other than the blonde Android herself, Android 18. As she quickly evidences by defeating Super Saiyan Vegeta, Android 18 is a massive threat to the Z Fighters before eventually aligning herself with them in subsequent sagas.
During Dragon Ball Z's Buu Saga, the series reveals the King of the Demon Realm, Dabura. Although Dabura doesn't end up accomplishing much before being turned into a cookie and eaten by Majin Buu, he does fight Gohan's Super Saiyan 2 form to a stalemate, demonstrating how powerful he is as a fighter.
Arguably, the biggest revelation from Dragon Ball Super is the reveal that there are multiple other universes, each of which has powerful fighters and gods that rival those of the Z Fighters and Universe 7. One noteworthy group from the multiverse is the Saiyans of Universe 6, which includes the powerful Saiyan warrior known as Cabba.
Dragon Ball Super: Super Hero revisits a variety of elements from DBZ's Android Saga, including the return of Red Ribbon Army-created biomechanical creations capable of fighting the Z Fighters head-on. This time around, Dr. Hedo (the grandson of Dr. Gero) is the mastermind who creates new Androids — Gamma 1 and Gamma 2, to be specific.
In addition to Gamma 1 & Gamma 2, Dragon Ball Super: Super Hero introduces another creation of Dr. Hedo's that is significantly more dangerous. Cell Max lacks the intelligence or self-awareness of his predecessor, but what he lacks in wit, the creature more than makes up for with raw firepower.
Dragon Ball Super introduces Beerus, Whis, and a host of new deities to the story of Son Goku and the Z Fighters. Beerus and Whis — the God of Destruction and Angel assigned to Goku's universe — spend plenty of time training and/or fighting Dragon Ball's main character, but the same can't be said for their peers.
Beerus is the measuring stick for Goku and Vegeta as their power starts to creep into the level of the gods; however, it's actually the Angel Attendant of Universe 7, Whis, who is their universe's strongest deity. The Z Fighters' two primary fighters have seen Whis' strength firsthand on numerous occasions during their training, yet neither of them has ever fought any of the Angels from Dragon Ball's other universes.
The Angels all wield immense power in Dragon Ball Super, and of their ranks, none is presented as being more powerful than the Grand Minister. Much like each of the multiverse's Angels serves as a guiding hand to their respective God of Destruction, the Grand Minister helps Zeno himself oversee the multiverse.
Dragon Ball DAIMA heavily incorporates two elements introduced to the Dragon Ball franchise during the Buu Saga: the Majin and the Demon Realm. In terms of lore and world-building, this storyline manifests in the reveal that the multiverse was created by an ancient figure known as Super Majin Rymus, who did so at the behest of an ancient Ruler of the Demon Realm.
In the Dragon Ball franchise, no character possesses more all-encompassing power than the creator of the multiverse, Grand Zeno. Pretty much nothing is known about the omnipotent being's origin, but it is clearly stated that he is responsible for presiding over all 12 of the universes in Dragon Ball, making him an easy choice as the strongest character in the entire franchise.