Summary of this verse
The Dragon Ball series is a franchise mostly consisting of manga and anime. It revolves around a boy named Son Goku and how he grows up to become the protector of Earth, along with his allies, as well as his sons, Gohan and Goten. In Dragon Ball and Dragon Ball Z, the manga is the original canon, and the anime is generally not included due to the huge amount of filler. Dragon Ball Z Kai lacks a lot of the contradictions, and I treat it as canon since it stays more true to the manga. There are a lot of video games based off of the series, but those are likely a separate canon. Dragon Ball GT is stated to be a side story to the original Dragon Ball Z, and has several contradictions with Dragon Ball Super. The movies are stated to be a separate canon, with the exception of Dragon Ball Z: Battle of Gods and Dragon Ball Z: Resurrection F.
Power of this Verse (Original)
The Dragon Ball-verse is extremely powerful. In it's early days, it had Wall to Island level characters. At the beginning of Dragon Ball Z, it reached Moon level via Piccolo easily destroying a moon, with Nappa being Small Planet level and Vegeta being Small Planet level. Frieza and other characters brought the series up to Star level, with Androids 16, 17, and 18 being Large Star level, as well as Cell. Super Perfect Cell and Super Saiyan 2 Gohan reached the power to destroy a Solar System, which is confirmed by multiple guidebooks. In the Buu Saga, a lot of characters reached significantly higher levels, with Kid Buu being able to gradually obliterate a galaxy in the Dragon Ball Z anime and Dragon Ball Z Kai. In Dragon Ball Super, Dragon Ball Z: Resurrection of F, and Dragon Ball Super, they reached even higher levels.
In the beginning, the characters are generally in the Hypersonic range. In the Saiyan Saga, plenty of the Z-Fighters reached Sub-Relativistic. By the Frieza saga, they were able to reach FTL speeds. In the newest media, a lot of the characters made it into the MFTL+ range, usually billions to trillions of times FTL.
In Dragon Ball Super, Dragon Ball Z: Resurrection of F, and Dragon Ball Super, Goku, Beerus, and Vegeta reached a level where they could easily destroy a universe. Beerus was already leagues above Goku and Vegeta. In the Universe 6 Saga, Goku fought Hit, who could create an entire parallel world with Time Skip, placing Goku at Universe level+. In the Future Trunks Saga, Fusion Zamasu and Vegito far surpassed the Universe-busting Goku and Vegeta (probably Beerus too), making them Multi-Universe level. Also, Goku and Vegeta went through several power boosts allowing them to fight Super Saiyan Rose Goku Black, who had previously been leauges above them. Fusion Zamasu threatened multiple timelines in his Soul Form, and only Zen'o could stop him. Speaking of Zen'o, he is surpassed by nobody in the multiverse, which originally was 18 universes.
Power of this Verse (New, To be continued)
The Dragon Ball-verse is an extremely powerful verse, one of the strongest anime verses out there, though far from the strongest. Most characters don't have a lot of hax, but the top tiers and god tiers have an amazing amount of Attack Potency, Durability, and Speed. The lowest characters are normal humans, and a few Wall level characters. Some characters are Tier 8 to Tier 6, while nowadays a lot of the characters are Tier 5 to Tier 2. The main character, Goku, started at Tier 9, but by the beginning of Dragon Ball Z, he reached Tier 5. In Dragon Ball Super, Goku and Vegeta's lowest feats are Tier 4, and at their peak they are Tier 2, as well as the Gods of Destructions, the Angels, and Zen’ō (AKA the Omni-King).
The verse has a huge range of feats, from Tier 9 all the way to Tier 2. The verse is far faster than many people think, with Saiyan Saga characters reaching Sub-Relativistic+ speeds, and Goku and Final Form Frieza reaching FTL speeds in the Frieza Saga. Most of the characters don't have a lot of good hax, but some characters, such as the God of Destructions, the Angels, and Zen’ō, have some suprisingly effective hax compared to the lower tiers. Attack Potency and Speed are some of their greatest attributes in a VS Debate.
In the very beginning of Dragon Ball, Goku starts off as Wall level for being able to smash thick wood apart and crush small boulders to pieces by squeezing them in his hands. Later in Dragon Ball, Goku reaches Tier 8 via defeating Tao Pai Pai and fighting on par with Tien, who destroyed the World Martial Arts Tournament Ring. In the King Piccolo Saga, Goku reaches Tier 7 for fighting King Piccolo, whose strongest attack was this powerful. When Goku became a teenager, he reached Tier 6 for fighting on par with Piccolo Jr, whose Hyper Explosive Demo Wave razed a small continent, and it was calced at Island level.
By the Saiyan Saga in the beginning of Dragon Ball Z, we have Piccolo at Tier 5 for one-shotting the moon and making it explode. Goku and Raditz scale to this for the former being equal to Piccolo, and the latter for being superior to both Goku and Piccolo. Later in the Saiyan Saga, Nappa and Vegeta are far stronger than Raditz, with Vegeta stating that he could destroy Earth, and multiple other sources confirming this. Gohan, Goku's son, was trained by Piccolo after he killed Raditz and Goku (the later was holding the former still so he could be finished off) at the same time, and he became stronger than Raditz, but weaker than Nappa. Krillin was at the same level when fighting Nappa and Vegeta. As an Ooozaru, Vegeta is not Large Planet level, but he still powerful enough to overwhelm Goku.
In the Namek Saga, Vegeta is healed from his life-threatening injuries from fighting Goku and his friends, and due to his Saiyan DNA, he becomes even stronger via a Zenkai boost. This allows him to surpass Cui, one of Frieza's minions who was as powerful as Vegeta was before his Zenkai boost. He also defeated Dodoria, who was even more powerful than Saiyan Saga Vegeta. Vegeta fought Zarbon, but lost due to the latter's transformation. Vegeta was almost killed, but he was healed in a Restoration Tank, and as a result, he became even stronger, defeating Zarbon in his transformed state. Gohan and Krillin had their potential unlocked by the Grand Elder Namekian (AKA Guru), and they became as strong as Vegeta was back in the Saiyan Saga. When Goku had arrived at Namek after recovering from the fight with Vegeta on Earth and training in his spaceship on his way to Namek, he became strong enough to dominate the Ginyu Force, including Jeice, Burter, and Recoome, the former of which had easily defeated Vegeta at the time. Goku was even able to surpass Captain Ginyu, who was stronger than all of the other members of the Ginyu Force. Vegeta was also able to surpass Ginyu after recovering from the battle with Recoome.
In the Frieza Saga, First Form Frieza is far stronger than any of the previous enemies the heroes (and Vegeta) have face. He is at least High 4-C via destroying Planet Vegeta with a finger. Since this feat was casual, he is likely close to 4-B. Vegeta's Zenkai Boosts have allowed him to surpass First Form Frieza, yet he was weaker than Frieza's Second and Third Form. After permanently fusing with Nail, Piccolo became strong enough to fight Second Form Frieza, but he was no match for Third Form Frieza. Vegeta had Krillin inflict a life-threatening injury on him, and after Dende healed him, he became stronger than Third Form Frieza. Due to Frieza's feat being casual, Third Form Frieza, and therefore Vegeta after his final Zenkai boost should be 4-B as well. Frieza transformed into his Final Form, and he became strong enough to torture Vegeta and even kill him.
When Goku came back after being in a Restoration Tank again, he became strong enough to damage Frieza, but the latter was holding back, and not even a Kaioken x20 Kamehameha could severely damage him at 50% of his power. After witnessing Krillin's death, Goku became a Super Saiyan, fodderizing Frieza. Full Power Final Form Frieza was enough to give Super Saiyan Goku some trouble, but in the end, he lost.
In the Android Saga, Frieza is rebuilt and is no weaker than his previous self. When he arrives on Earth, Future Trunks arrives and as a Super Saiyan, he easily slices Frieza into tiny pieces before disintegrating him with a ki blast. After returning to Earth, Goku is powerful enough to easily block blows from Trunks' sword with a mere finger. After 3 years' training, Vegeta had become a Super Saiyan. Goku as a Super Saiyan was far more powerful than Android 19 was, but he was affected by a heart virus, which allowed 19 to defeat him. Vegeta as a Super Saiyan had become powerful enough to fodderize Android 19, who was about as strong as Frieza. He was as strong as Goku, if not slightly stronger.
Android 17 and Android 18 are released by Dr. Gero (AKA Android 20) and they betray and kill him. 18 is far more powerful than 19, matching and surpassing Vegeta in power, even being able to break his arm.
Cell, a creation from the future, is a far greater threat than 17 and 18. Even after Piccolo fused with Kami, Cell after devouring the people of a town was far stronger than he and 17 were. Android 16 was slightly superior to Imperfect Cell, and since he was an actual android, unlike 17 and 18 who were technically cyborgs, he couldn't drain his energy like he did to the townspeople he devoured.
Cell finally suceeded in absorbing Android 17, becoming Semi-Perfect Cell. In this form, he was unharmed by attacks from Androids 16 and 18, and he could easily outpace them and cut them off from escaping. Tien was able to hold back Cell with his Tri-Beam (AKA Kikoho), but due to it's overuse his body was drained of energy. This doesn't mean Tien himself is on the level of Semi-Perfect Cell, as he hasn't shown an increase in power on his own, but it means his Kikoho is far more powerful than he normally is.
Androids 16 and 18 manage to escape thanks to Tien and Goku, the latter of whom came to save the former after his energy ran out from using the Kikoho too many times. After Cell tries destroying islands to get 18 to come out, Vegeta interrupts, having come out from the Hyperbolic Time Chamber, and challenges him.
Vegeta transforms into an Ascended Super Saiyan and easily dominates Semi-Perfect Cell. Later, Vegeta is able to slightly harm Perfect Cell, yet he is still outclassed by him. Both Vegeta and Perfect Cell are Large Star level+, far higher than almost any other character at that time.
Vegeta himself stood no chance against Cell, but he was able to obliterate his arm via a new attack, the Final Flash. It was stated that if Cell had taken the full force of the blast, he would have been killed, putting the Final Flash at Large Star level+. After Cell casually defeated Vegeta, Trunks became Ultra Super Saiyan (3rd grade Super Saiyan).
Cell stated that Trunks' new form had more raw power than he did at the moment, but due to the latter's speed decrease, Cell was able to defeate Trunks after the latter held his own for a while.
After Goku and Gohan came out of the Hyperbolic Time Chamber, both of them could go Super Saiyan Full Power, which gave them the ability to use the transformation in a natural state, and the users can be relaxed and even cheerful when in the form. Because of this, the form lacks the drawbacks that the other grades of Super Saiyan have.
During the Cell Games, Super Saiyan Full Power Goku is able to keep up with Perfect Cell, but the latter was holding back during the fight. After Goku gives up, Gohan comes to fight Cell. As a Full Power Super Saiyan, Gohan is stronger than Goku, but he still is unable to beat Cell.
After Android 16 is killed by Cell, Gohan unleashes all of his power, becoming a Super Saiyan 2. In this form, he easily dominates Perfect Cell, but he continues toying with him. Cell is punched so hard he regurgitates Android 18 and he tries to blow himself up with everyone else.
Goku teleports with Cell to King Kai's planet, sacrificing himself. Cell somehow survived the explosion via regenerating from one cell. Due to his Saiyan cells, he comes back even stronger, to the point he is effortlessly able to one-shot Ascended Super Saiyan Vegeta.
He even states to have enough ki to destroy the whole Solar System. This statement has been confirmed by multiple guidebooks, showing that Cell wasn't bluffing. Gohan's Kamehameha was also shown in various guidebooks to be able to wipe out a Solar System, and he should scale to Cell, since he was able to match him. This is even further supported by first form Frieza having a Large Star level+ feat.
Thanks to a distraction from Vegeta, Gohan manages to finish Cell off and destroy him completely.
In the seven years of peace following Cell's demise, Chi-Chi, Goku's wife, gave birth to a second child, Goten.
Goten has a lot of power, becoming a Super Saiyan at the age of 7, just from training with his mom. His power is barely below that of his best friend Trunks (not the one from the future), and together they are enough to fight on par with Android 18. Gohan, now a teenager, has focused more on his studies than training, and he hasn't gotten any stronger, with Vegeta even commenting on how Gohan had more power while fighting Cell. Goku and Vegeta have both reached Super Saiyan 2, and they are superior to Gohan to an unknown degree.
A new monster appears in this saga, Majin Buu. In his Kid Buu form, he is able to wipe out galaxies over time, and is stated by Supreme Kai to have wiped out multiple galaxies, so he is likely at the higher end of Multi-Solar System level, or Multi-Solar System level+. His Fat Buu form is weaker, but not too far behind, as he was able to put up a fight against him. Super Saiyan 2 Vegeta is likely Multi-Solar System level as well, but to a much lesser extent than the two forms of Buu. Super Saiyan 3 Goku was able to dominate Fat Buu without even trying, and could have beaten Kid Buu if he had ended the fight quickly.
Super Buu is by far Buu's strongest form, being a perfect combination of the good and evil halves of Buu. Base Super Buu was superior to Goten and Trunks' fusion (Gotenks) in their Super Saiyan forms, and fought on par with Gotenks even as a Super Saiyan 3. Gohan's potential was unlocked by the Supreme Kai, and he could dominate base Buu and defeat him with Piccolo absorbed, but he could not beat him while Gotenks was absorbed. After Buu absorbed Gohan, he was so powerful that only the Potarra fusion of Goku and Vegeta, Vegito, was above him.
Following Dragon Ball Z is Dragon Ball Super, where the characters really start to get powerful.
Supporters and Opponents of the Series
Red Ribbon Army
Gods of Destruction
Despite some contradictions, I consider Dragon Ball Kai to be part of the main canon, since it has far less contradictions than the original Dragon Ball Z anime and it was stated that DBZ Kai was specifically made to be more similar to the original manga. Some contradictions, such as Frieza and the other villains in Hell, can be considered a retcon, as Hell's appearance was changed in Dragon Ball Z: Resurrection of F and Dragon Ball Super.