There was a time when Bleach was one of the top shonen series in the world, and the Thousand Year Blood War arc has justifiably reignited interest in the series. People love Bleach because of the characters and power systems, which culminate in good action sequences. An Arrancar is created when a Hollow removes their mask and gains powers similar to a Soul Reaper, but the process was not perfected until Aizen took control of Hueco Mundo.
These new Arrancar were much stronger, and they wielded zanpakuto just like Soul Reapers. When they released their zanpakuto, their strength would increase exponentially, and they would gain new abilities. Their appearances would also change, and although each Resurreccion form looked good, some looked far cooler than others.
10 Loly Aivirrne - Escolopendra
It is true that Aizen has many powerful abilities at his disposal, but even he needed help with menial tasks, which is where Loly Aivirrne comes in. She served as one of Aizen's aides, and she was infatuated with him, which is why she hated Orihime and the interest he showed her.
Loly may be one of the weaker Arrancars, but her Resurreccion actually looks cool. It is called Escolopendra, and it gives her body a centipede-like appearance. She gains armor over her legs, arms, chest, and neck, and her arms resemble centipedes without heads.
9 Abirama Redder - Aguila
Abirama Redder served as one of Baraggan's six Fraccion, and he was ultimately defeated by Lieutenant Izuru Kira during the Fake Karakura Town arc. Even for an Arrancar, he was quite rude and impulsive, and he seemed to like violence.
His zanpakuto was called Aguila, and when he released it, he became an eagle-human hybrid. With the exception of his white eagle's head Hollow mask, Abirama's entire body was covered in dark red feathers. He sported massive wings and both his arms and legs were replaced with razor-sharp talons
8 Szayelaporro Granz - Fornicaras
Szayelaporro Granz may have not been the strongest Espada, but he was a narcissistic, cruel, and sadistic scientist. He releases his zanpakuto by swallowing it, and in doing so, his entire body swells up with spiritual energy.
The end result is rather flamboyant, as the lower half of Szayelaporro's body acquires a layered-dress appearance, while his upper-body gains a segmented form-fitting outfit. He gains four branch-like appendages on his back which have red strands resembling falling drops. This drop pattern can be seen in his hair, and on his sleeves, and his finger becomes elongated.
7 Nelliel - Gamuza
When Nel was first introduced, she looked like a small child who was always frightened and crying, but it was later revealed that she was actually Nelliel, the former 3rd Espada. While in her mature form, she is far more intelligent, composed, and sophisticated, and she can use her Resurreccion.
It is called Gamuza, and it transforms her into a brownish-green centaur. The horns on her Hollow mash grow and become more curved, framing the sides of her face, and she gains white spaulders that cover her shoulders and neck. She wields a double-sided lance, which makes her look like a medieval jouster.
6 Coyote Starrk - Los Lobos
Stark's death was tragic because he died alone, after finally meeting individuals who could withstand his overwhelming spiritual energy. Lilynette was his only Fraccione, but she was also a fragment of his soul, which is why he needed her in order to use his Resurreccion.
While in his Resurreccion, Starrk looks like a gunslinger from the Wild West. Lilynette's mask becomes an eyepiece, and he gains a pair of pistols. He gains a gray fur-lined jacket over a double-breasted vest and elbow-length fur armbands. While in this form, Starrk also obtains skin-tight pants with knee-high fur leggings and fur-covered holsters.
5 Yammy - Ira
When he was introduced, Yammy was the 10th Espada, but it was later revealed that he becomes the 0 Espada when he releases his zanpakuto. Yammy takes on a kaiju-like appearance by growing to a colossal size. His upper torso is roughly the same, but his lower body now has eight large, white elephant-like legs and a bony tail club.
Yammy's power comes from his rage, and when he reaches a certain level of anger, his Resurreccion evolves. In this state, he becomes even larger, but he loses the tail and extra legs for a bulky ape-like appearance which includes exposed vertebrae and more pronounced horns.
4 Tier Harribel - Tiburon
Tier Harribel is a Vasto Lorde who became the 3rd Espada and the de facto ruler of Hueco Mundo, making her one of the strongest female characters in Bleach. Before becoming an Arrancar, she looked like a humanoid shark, and she looks even more human after releasing her zanpakuto.
She gains a skirt made of bones and spine-like structures that run from her stomach to her chest. She also obtains knee-length boots and elbow-length gloves. Her Hollow mask becomes a neck collar and shoulder guards, and she has ribbon-like protrusions on her back. Her zanpakuto takes the form of a massive shark tooth with gill marks.
3 Grimmjow - Pantera
Grimmjow was one of the first Espada to appear, and he gave Ichigo one of his toughest and best fights. He was ranked 6th, and before becoming an Arrancar, he was an Adjuchas-level Menos with a panther-like appearance, which explains why his zanpakuto was called Pantera.
His hair becomes a long mane of wild blue hair, and he gains cat-like ears, while his hands become black claws and his feet turn into clawed paws. His clothing transforms into form-fitting armor, and he gains sharp, curved blades on his calves and forearms.
2 Baraggan - Arrogante
Before Aizen appeared, Baraggan ruled over most of Hueco Mundo as its king, which explains why he was the 2nd Espada. When he releases his zanpakuto, he amplifies his Respira ability, which causes accelerated aging, and this is fitting because he literally looks like a God of Death.
His body is nothing more than a skeleton, but he wears a golden crown and matching armbands. He wears a purple cloak with an impressive fur collar, which covers his neck and the ends of his cloak.
1 Ulquiorra Cifer Segunda Etapa
Ulquiorra was the 4th Espada, and he was the only member of the group who possessed a second Resurreccion, making him one of the strongest Hollows in Bleach. In terms of aesthetics, it is a good thing he had a second form because his normal Resurreccion is not very impressive.
With Segunda Etapa, Ulquirra looks like a demon. His Hollow mask is completely gone, and he retains his large bat-like wings, which look more ominous because his slender-white torso is fully exposed. His waist is covered with black fur, and so are his arms and legs, and he has a whip-like tail which he uses for attacks.