As SingerOfTheFall pointed in his answer Captain Byakuya stated that:
Even the four noble families, whose members are always exceptionally
talented, have only a member capable of bankai every few generations.
At wikipedia states that:
Only 4 non Captains in the Gotei 13 to have achieved Bankai
Genryūsai Shigekuni Yamamoto (山本元柳斎 重國 Yamamoto Genryūsai Shigekuni)
Ryūjin Jakka's bankai "Zanka no Tachi" (残火の太刀?, lit. "Long Sword of
the Remnant Flame") upon release causes all of the flames produced by
Yamamoto to disappear into the blade. The bankai is comprised of four
abilities based on the cardinal points:
- "Zanka no Tachi - Higashi (East): Kyokujitsujin" (残火の太刀･東 旭日刃) in which all the flames are concentrated on the edge of the blade,
incinerating everything it touches
- "Zanka no Tachi - Nishi (West): Zanjitsu Gokui" (残火の太刀･西 残日獄衣) where Yamamoto envelops his whole body in flames, reaching up to
- "Zanka no Tachi - Minami (South): Kakajuuman' Okushi Daisoujin" (残火の太刀･南 火火十万億死大葬陣) - this techique resurrects the burned and
incinerated dead which were struck down by the blade using its burning
state, it is roughly translated to "great army of the 10 trillion
buried by flames".
- "Zanka no Tachi - Kita (North): Tenchi Kaijin" (残火の太刀・北 天地灰燼) - a powerful slash attack, incinerating everything in one fell swoop.
Translated as "heaven and earth are burned to ashes".
Chōjirō Sasakibe (雀部 長次郎 Sasakibe Chōjirō)
His bankai is "Kōkō Gonryō Rikyū" (黄煌厳霊離宮, lit. "Yellow-Glittering
Royal Villa of the Stern Spirit") can produce a bolt of lightning from
the blade which extends and transforms into a dome of lightning,
stationed far above the users head and fastened to the ground by a
large number of lightning pillars. These pillars can be controlled at
will to shock the opponent.
Shunsui Sōzōsuke Jirō Kyōraku (京楽 次郎 総蔵佐 春水 Kyōraku no Jirō Sōzōsuke Shunsui)
Unlike other Soul Reapers, Shunsui possesses paired zanpakutō called
Katen Kyōkotsu (花天狂骨?, lit. "Bones of Heavenly Blooming Madness").
While the blades are normally two daisho swords, their Shikai state
resemble dao or falchions. When released with the command "Flower Wind
Rage and Flower God Roar, Heavenly Wind Rage and Heavenly Demon Sneer"
(花風紊れて花神啼き 天風紊れて天魔嗤う Hana Kaze Midarete Kashin Naki, Tenpū Midarete
Tenma Warau), Katen Kyōkotsu gains the ability to "turn children's
games into reality." One such game, Bushō Goma (不精独楽?, Lazy Spinning
Top), involves spinning around wind like a top. Another, Takaoni (嶄鬼,
Mountain Demon), declares that whoever is the highest is the winner. A
third technique, Kageoni (影鬼, Shadow Demon), forces the players to
alter their own shadows; whoever steps on a shadow, even their own, is
declared the loser. The fourth game is known as Iro-Oni (艶鬼, Colored
Demon) where players call out color and then slice the enemy where
that color is displayed. However, if the color is not on the body of
the person who called it out then the damage given is minimal; the
more that the declared color is prevalent on the declarer's body, the
more damage the attack will commit. A fifth game is called Daruma-san
ga Koronda (だぁるまさん が こぁろんだ, The Dharma Doll Fell Down), a game
similar to "Red Light Green Light". The sixth and final game is called
Kageokuri (影送り, Silhouette Sending) which is a game where if a person
is staring hard enough at another person's shadow, then their opponent
creates after images of themselves. Katen Kyōkotsu's bankai is called
Katen Kyōkotsu: Karamatsu Shinjū (花天狂骨枯松心中, "Heavenly Bloom Madness
Bone: Withered Pine Lovers' Suicide"), which he uses only when his
allies are at a safe distance from himself. When released,
Shunsui's bankai covers a large area around Shunsui in an aura. This
aura changes others' perception of the surrounding environment, making
them perceive it as darkened, bleak and gloomy, and causes others to
feel varying levels of melancholy and despair. While it maintains
its shikai form, its bankai allows Shunsui to manifest various
stories, which can kill opponent easily. It also manifests the spirit
of Shunsui's zanpakutō, a Feudal-Japan-style mistress referred to as
"Sakuranosuke" who created a silent kunoichi bodyguard from her being
to hold Shinken Hakkyōken until Nanao eventually asks for it.
Soi Fon (砕蜂（ソイフォン） Soi Fon, pinyin: Suì Fēng), born Fon Shaolin (蜂 梢綾（フォン シャオリン） Fon Shaorin, pinyin: Fēng Shaolíng)
Soi Fon's Zanpakutō is Suzumebachi (雀蜂?, literally translated as
Suzumebachi's Bankai, Jakuhō Raikōben (雀蜂雷公鞭, lit. "Hornet Whip of the
Thunder Immortal") composes of a greatly enlarged version of the
shikai form that encases the entirety of Soi Fon's arm, which she
mentions as being bulky and incapable of concealing, and thus unsuited
for use in missions requiring stealth. In this form, Suzumebachi
becomes a long-range weapon and looks like a large rocket launcher;
its main offensive capability allowing Soi Fon to launch a high-speed
projectile that resembles a large missile. The thunderous recoil
produced by the weapon requires Soi Fon to be anchored to a nearby
stationary object via an enhanced cloth-like material (which doubles
as armor) called Ginjōtan (銀条反, lit. "Stripe of Inverted Silver").
Gin Ichimaru (市丸 ギン Ichimaru Gin)
Gin's Bankai is "Kamishini no Yari" (神殺鎗 which means "God Kill Spear.")
By adopting a stance where he firmly grips Kamishini no Yari with both
hands and places the Zanpakutō's hilt squarely on the center of his
chest, Gin is able to utilize the tremendous extension and contraction
properties of his Bankai to an even more terrifying extent than its
normal state. This occurs in the form of a piercing maneuver where the
extension and contraction of the blade becomes almost completely
unseen to even the most diligent of observers.
Shūsuke Amagai (天貝 繍助 Amagai Shūsuke)
Amagai's Zanpakutō is Raika (雷火, roughly "Flash of Lightning").
Raika's Bankai, Raika Gōen Kaku (雷火豪炎殻, literally "Lightning Flash
Flame Shell"), enlarges the blade and creates a giant conch-shaped
guard worn across Amagai's arm, with the handle of the blade hidden
inside it. This form gives him greater control of his fire attacks,
his most powerful technique creating giant dragons of fire to encircle
and crush his foe.
Yachiru "Retsu" Unohana (卯ノ花 烈 Unohana Retsu)
Unohana's Zanpakutō is Minazuki (肉雫唼, roughly "purify the flesh").
Her bankai is Minazuki (皆尽?, "All Things' End"). When activated it
releases a thick, oily substance from the blade. Its powers have yet
to be revealed. Minazuki appears as freed Zanpakutō spirit in the
Zanpakutō Unknown Tales anime arc with Minazuki's form being a mute
figure of unknown gender in a hooded robe, pretending it was
imprisoning Yamamoto. Unohana has a scar on her collarbone inflicted
by Zaraki Kenpachi when they fought prior joining the Gotei 13. She is
also a skilled swordsman and have mastered all kind of swordsmanship
techniques. In a new release of the manga, she is still shown fighting
Zaraki Kenpachi. She then calls forth her Bankai, saying "Minazuki"
and it appears that her blade is releasing blood as she slashes
Captain Zaraki. It also appears that in an illusion, their flesh is
peeling away from their bodies, and they are still fighting but as
skeletons. It is still difficult and to early to truly understand what
her Bankai actually does.
Byakuya Kuchiki (朽木 白哉 Kuchiki Byakuya)
His Bankai is Senbonzakura Kageyoshi (千本桜景厳, "Vibrant Display Of One
Thousand Cherry Blossoms")
When released, his blade disappears, and a thousand blades, resembling
sakura petals, come upon his opponent and slash them multiple times.
Hihiō Zabimaru turns his sword into a skeletal giant-snake like sword that
has a head. It can dissemble and reform at Renji's will and can shoot
focused reiatsu at the head.
Sōō Zabimaru is compacted into form predomately worn by Renji
with the snake skull smaller and affixed over Renji's right hand as a
combination blade gauntlet and shield while a skeletal simian arm
hovers just slightly above Renji's right arm. Sōō Zabimaru's signature
technique Zaga Teppō is a close range attack where Renji uses his
spiritual pressure to conjure a large snake skull that incinerates
whatever it bites down on.
Source about Renji's bankai
Sajin Komamura (狛村 左陣 Komamura Sajin)
Komamura's Zanpakutō is Tengen (天譴, literally "divine punishment",
translated in the English manga as "sword of heavenly retribution").
Tengen's bankai, Kokujō Tengen Myō'ō (黒縄天譴明王, roughly "vidyarāja of
black-roped divine punishment", translated in the English manga as
"divine retribution, black ropes of ruination") brings forth the
entire giant, which also copies Komamura's movements.
Shunsui Kyōraku (京楽 春水 Kyōraku Shunsui)
His bankai is unknown, but when asked by the Espada Coyote Starrk to
show it to him, Ukitake warns him not to reveal it where so many
people could witness it. Katen Kyōkotsu (花天狂骨) appears as a free Zanpakutō
spirit in the Zanpakutō Unknown Tales anime arc as two separate female
beings: a Feudal-Japan mistress and her silent ninja bodyguard,
wielding Shunsui's swords.
Kensei Muguruma (六車 拳西 Muguruma Kensei)
Kensei's bankai is named Tekken Tachikaze (鐡拳・断地風, lit. Iron Fist
Earth-Severing Wind). The combat knife transforms into two bladed
Kaname Tōsen (東仙 要 Tōsen Kaname)
The Zanpakutō Tōsen uses originally belonged to his now-deceased
friend and is called Suzumushi (清虫, literally "pure insects", but read
as "cricket"; translated in the English manga as "bell bug").
Suzumushi's bankai, named Suzumushi Tsuishiki: Enma Kōrogi (清虫終式紅閻魔蟋蟀,
literally "Suzumushi, final style: Enma cricket") creates a large,
black dome centered at Tōsen's location and anchored to the ground
with ten rings. Anyone within the dome loses four of their five
senses, retaining only the sensation of touch. The weakness of this
technique is that whoever is touching Suzumushi's hilt is immune to
the dome's effects, so anyone able to grab Suzumushi recovers their
senses for as long as they remain in contact with the hilt.
Ikkaku Madarame (斑目 一角 Madarame Ikkaku)
Ikkaku's Zanpakutō is Hōzukimaru (鬼灯丸, referring to the Japanese name
for the winter cherry, meaning "demon light").
Hōzukimaru's bankai, named Ryūmon Hōzukimaru (龍紋鬼灯丸, literally
"dragon-crest demon light"), takes the form of three oversized weapons
connected by a thick chain: two blades in each of his hands and a
fan-shaped blade, adorned with a carving of a Chinese dragon, which
floats behind him. Aside from the increase in power, his Bankai offers
no special abilities, and is noted to be unusual for a bankai in this
Mayuri Kurotsuchi (涅 マユリ Kurotsuchi Mayuri)
Mayuri Kurotsuchi's Zanpakutō is Ashisogi Jizō (疋殺地蔵, roughly
Ashisogi Jizō's bankai, named Konjiki Ashisogi Jizō (金色疋殺地蔵,
literally "golden leg-cutting Buddha", translated in the English manga
as "divine leg-cutting Buddha"), takes the form of a giant caterpillar
with a baby's head and a silver halo. The creature breathes a
poisonous derivative of Mayuri's blood which is lethal to anyone who
breathes it, aside from himself and Nemu. It can also run through
and skewer opponents with the multiple blades that erupt from its
chest. Mayuri has physically modified his bankai so that it will
self-destruct and return to its sealed state if it attacks him. It is
also shown that Mayuri changes the poison he uses every time he shows
Rukia Kuchiki (朽木 ルキア Kuchiki Rukia)
Hakka no Togame increases the area of influence of Rukia's
ability to reach the temperature of absolute zero. Upon release, a
pillar of cold mist rises up into the air from where Rukia is and
covers a wide area in her vicinity. Anything within the area of
influence of the mist is frozen. Once frozen solid, victims crumble
away within seconds. Physical contact with Rukia herself causes other
people to begin freezing solid because of how cold she is. While it is
a powerful Bankai, it is also a difficult one, as the slightest
mistake could kill Rukia. Because Rukia is physically affected along
with everything else in her vicinity, the amount of time she can use
her Bankai appears severely limited, as prolonged use can potentially
cause her damage, so she is required to melt slowly when leaving this
state, otherwise she would risk damaging herself.
Source about Rukia's bankai
Shūsuke Amagai (天貝 繍助, Amagai Shūsuke)
Raika Gōen Kaku (雷火 豪炎殻, Lightning Flash Flame Shell): Amagai holds
out his Zanpakutō in front of him as fire swells around him. Raika
becomes a large and more detailed version of its former self. Raika
Gōen Kaku takes the form of an enlarged sword, and turns the edge of
the blade a crimson red color, with a hook at the end. The inner side
of the hook-blade sports several jagged edges. A large white shell
with a light-purple trim covers the hilt. A massive hollow
pauldron/shield with the handle is hidden behind it. The sword is
about as tall as Amagai in this form.