From Dragon Ball Z onward, transformations and dramatic power-ups were part and parcel with the Dragon Ball experience. Son Goku, Son Gohan, Vegeta, Frieza, Trunks, Cell, Son Goten, Broly, Cooler, and countless others have unveiled dramatic new forms that have changed the playing field and oftentimes changed the fight in their favor.
Of course, this hasn't always been the case. There have been transformations that were underwhelming and didn't change much in the grand scheme of things. Oftentimes, it's been Son Goku's new power-up that has saved the day or the villains that get the dramatic transformations that blow everyone away, leaving the likes of Vegeta, Piccolo, and Trunks seeming like so much chopped liver.
10 DRAMATIC: Super Saiyan
We'll start with the most famous transformation as well as the most obvious choice. The original Super Saiyan transformation by Son Goku while fighting Frieza on the Planet Namek isn't just one of the most exciting and dramatic moments in the series, but in anime as a whole.
It's Goku reaching his full potential (for now) and reaching heights of power on par with even the great Emperor Frieza. It's almost as dramatic when Vegeta, Son Gohan, Trunks, and Son Goten do the same, and it works as a stepping stone for other dramatic transformations throughout the series.
9 UNREMARKABLE: Super Saiyan 2
Super Saiyan 2 was the first step beyond the regular Super Saiyan form, and it was first achieved by Gohan while training in the Hyperbolic Time Chamber. Goku later achieves the form as well, and Gohan dramatically uses it in his final battle with Perfect Cell.
While that battle was fantastic, the aesthetic change between Super Saiyan and Super Saiyan 2 is very subtle and not all that interesting. The first Super Saiyan transformation was distinct and dramatic; you wouldn't notice the change between Super Saiyan and Super Saiyan 2 if characters didn't point it out.
8 DRAMATIC: Super Saiyan Blue
After Super Saiyan 3, Super Saiyan Blue/Super Saiyan God Super Saiyan is the next complete visual overhaul in the chain of Super Saiyan transformations. In a show where the power of most of the heroes is determined by what's going on with their hair, flipping the script and changing it blue was quite a development.
It was a heck of a reveal in Resurrection F when Goku achieves this form in his fight with the returned Frieza, and it has been used in several stunning fights since then. It's become the iconic look for Goku and Vegeta in Dragon Ball Super.
7 UNREMARKABLE: Super Vegeta/Super Trunks
During the Cell Saga, Vegeta and Trunks' training led them to achieve a new form of Super Saiyan where they use their ki to dramatically increase their muscle mass and physical strength.
Unfortunately, this also means that they are far slower and larger targets. Trunks was able to grow even larger than Vegeta, but they both were wiped out easily by Perfect Cell.
6 DRAMATIC: Legendary Super Saiyan Broly
Both the original and Super transformations of Broly have always been stunning. Like the Super Vegeta and Super Trunks forms, Broly's transformations result in him gaining incredible muscle mass and power.
However, Broly proved to be infinitely more deadly in this form and took a lot of effort and teamwork to bring down. In Dragon Ball Super Broly, it took Goku and Vegeta performing the Gogeta fusion and achieving Super Saiyan Blue to bring down Broly's powerful Super Saiyan form.
5 UNREMARKABLE: Full Potential
During their time fighting Frieza's army on the Planet Namek, Piccolo, Krillin, and child Gohan met with the Great Elder Guru of the Namekians and had their "full potential" unleashed.
It did little to help them in the subsequent fight with Frieza and his followers. It took Piccolo fusing with the dying Nail to even keep up with the likes of the Ginyu Force and the earlier stages of Frieza.
4 DRAMATIC: Golden Frieza
Ressurection F also brought about the arrival of Golden Frieza. This form of the Emperor gives him a shiny golden sheen and makes him powerful enough to even take on Goku in his Super Saiyan God form.
Each new enemy in Dragon Ball Z is exponentially stronger than the previous, but the Golden form of Frieza put him beyond the likes of Perfect Cell and Kid Buu. It took Goku going beyond the Super Saiyan God transformation to finally put Golden Frieza down.
3 UNREMARKABLE: Mecha Frieza
Frieza's arrival on Earth in a new cyborg form as Mecha Freiza as well as the presence of his father, King Cold, was a shocking return for the Frieza clan at the start of the Android Saga.
Unfortunately, this new Frieza and his large father proved nothing but mince-meat once Future Trunks arrived. Mecha Frieza and Cold were dead in the blink of an eye.
2 DRAMATIC: The Fusions
Gogeta, Vegito, Gotenks, Kefla, and other less-canon fusions have always been one of the most exciting parts of Dragon Ball. The idea is simultaneously so ludicrous yet so awesome that one can't help but relish when a new fusion is on the table. They first popped up during the Buu Saga.
Vegito, the Potara fusion of Goku and Vegeta, and Gotenks, the union fusion of Trunks and Goten, were the first to appear and battled Buu, but other versions of these specific fusions and fusions of other characters have succeeded the concept since then in Dragon Ball Z, Dragon Ball GT, Dragon Ball Super, and the affiliated videogames.
1 UNREMARKABLE: Ultimate Gohan
Ultimate Gohan is the final transformation that was granted to Gohan in Dragon Ball. It was granted to Son Gohan by the Kai Elder Kaioshin, and Gohan has been able to make this form a power on par with even Super Saiyan Blue since then.
However, it really didn't add much of a visual change for Gohan like other transformations, but it did allow Gohan to dominate Super Buu. Still, it wasn't enough to bring down Kid Buu, meaning Goku had to save the day once again on this one.