Ultimate Job Security: Captains are the strongest beings in the Soul Society, so they have the freedom to do a lot of what they want and get away with it. Even when Mayuri blows up his own squad, it doesn't damage his position as captain, because the law only prohibits captains from doing anything to other captains' soldiers. In Turn Back The Pendulum, Kiganjo never bothered turning up to captains' meetings - it was such a contentious point that other captains commented on it with disapproval. It didn't get him fired, however (he was later killed by Zaraki, but that was just because Zaraki wanted to prove his right to wear the 'Kenpachi' title). Zaraki spends most of his time sleeping and Kyoraku tries to avoid work to chase girls. Ukitake spends most of his time in bed sick, but his situation is justified since he has Tuberculosis.
Unfinished Business: The reason why shinigami have to perform konsou on spirits and why spirits might linger long enough to turn into hollows if they don't have konsou performed in time.
Unnecessarily Large Interior: Las Noches is a single building that appears to be the size of a small country. It doesn't seem to exist for any reason other than for Aizen to show off.
Unwitting Pawn: Muramasa's plan from the Zanpakuto Unknown Tales arc. It might qualify as a Roulette if Ichigo weren't so easy to manipulate. His original plan was to get inside Yamamoto's head in order to access his memories in order to free his former master, when Yamamoto set up a barrier to keep him out he staged a Zanpakuto rebellion to buy himself time. Ultimately, he tricked Ichigo into helping him break the barrier allowing him to access Yamamoto's memories and free Yama's Zanpakuto.
Ulquiorra defeats Ichigo with his released form. However, he still takes on a second release, something no other arrancar has been seen to possess, to not only kill him, but to defeat him with pure despair. Ichigo's hollowfied response takes this even further, beyond anything even Ulquiorra has seen a hollow be capable of doing.
Bankai is supposed to be the final release of a zanpakutou, the ultimate Super Mode. Then it's revealed Final Getsuga Tenshou exists... and that more than one character knows how to develop it.
Vampiric Draining: Hollows feed on spiritual energy as a secondary source of nourishment (the primary being the "hearts" of both living and dead Humans). Sources include humans, Soul Reapers and other hollows.
When the Menos Grande first appeared Rukia said she'd read in textbooks that only the Royal Guard can fight them. Ichigo could barely scratch it. Now that it's been confirmed that was a Gillian, the lowest level of a Menos Grande, and that any high seated shinigami can handle them. As the power levels of the main characters develop to lieutenant and captain levels, the Gillians have accordingly become regarded as mook-level threats.
Aizen starts out as a cool, composed, Big Bad who hands out Gambit Roulettes like they handed out Kool-Aid at Jonestown. Then he became Drunk with Power and his constant petty taunting reduced him from a Magnificent Bastard to Smug Snake. This was actually lampshaded in-universe and Urahara was even counting on it as part of his plan to help Ichigo defeat Aizen. It worked.
Ordinary hollows are the worst threat in the early stages of the story. Then this is ramped up when it's revealed there are giant versions of hollows called Menos Grande that only the Royal Guard are supposed to handle. Turns out Rukia's textbooks were wrong: any high seated officers can handle Menos Grande if they're Gillian level and captains and lieutenants can handle Adjuchas levels. Only the Vasto Lord level of Menos Grande gives captains trouble.
The Espada were modified arrancar of post-Menos Grande level, introduced to make the threat of the shinigami captain in the Soul Society arc look minor by comparison.
It's gotten to such an extent that the Vandenreich threat has been introduced in a way that makes the Espada look extremely underwhelming. It's even lampshaded in-universe when one Quincy captain easily defeats five Arrancars and complains that Aizen's followers were weak.
Villains Never Lie: Subverted with Ichigo, who expresses doubt that Aizen could have done the things he claims.
Visible Sigh: A comedic device the anime uses, often when a character feels another is being unduly emotional.
Wacky Parent, Serious Child: Isshin is a rather off-the-wall nutcase whereas Ichigo is usually extremely serious. It tends to come across as Ichigo being the more responsible of the two. That said, Karin is even more serious than Ichigo. Isshin/Karin interactions are therefore even more extreme than between Isshin and Ichigo.
Walking Shirtless Scene: Common occurrence for the rougher characters. Kenpachi, Renji, Ikkaku, Ichigo and so on all get their bare-chested moments as a result of the fights they get into. Many of these instances double as Fanservice.
Walking Swimsuit Scene: The Beach Episode is pure fanservice, with all the female characters posing one-by-one to show off their costumes to the audience and then spending the entire episode in them.
The Arrancar Arc is set against the backdrop of the Winter War, a battle between the Arrancar and the Shinigami.
The Thousand Year Blood War Arc is the culmination of a thousand years of warfare between the Quincies and the Shinigami.
War Is Hell: A prominent theme about Bleach is that there is a distinct lack of "happy" deaths. When people die here, they invariably die in rather ugly ways, from decapitation to bifurcation and incineration, among other things. If their deaths are not particularly nasty (see Starrk), their scenes are still executed in incredibly depressing ways. Even if they're particularly nasty characters, well, their deaths may be deserved, but in each case, Kubo refuses to glorify how they died (see Driscoll) by making it as gruesome as he can. If they do accept their fate gracefully, Kubo consistently shows that, despite their peace at the prospect of death, their compatriots are affected in negative ways (Kaien to Rukia, Ichimaru to Rangiku and Unohana to Zaraki). Even if it doesn't lead to death, several characters get permanent scars, lose their limbs, suffer several severe sets of wounds, or end up so traumatized by their experiences that it influences their personalities and philosophies later in life (Kira, Hisagi). This all comes to a head during the Vandenreich arc, where the Stern Ritters' pragmatism seriously cripples much of the Shinigami and defies a multitude of Shonen battle cliches as a result. Aizen, himself a former teacher, once recited one such a commandment that all cadets are taught to in the Spiritual Arts Academy.
Watching the Sunset: In the anime, Hitsugaya likes to hang out in a place that has the best view of the sunset because it reminds him of his childhood days spent with Momo, where they eat watermelons while watching the sky.
Weakened by the Light: Espada #9 Aaroniero Arruruerie can't stand sunlight and can't maintain or perform his shape-shifting in the light.
Weapon As Familiar: The Zanpakuto have Shikai (changes form of your sword and gives an appropriate ability to it) and Bankai (where your sword turns into an effect or creature with an increase in the Shikai ability and a few variations on it). Zanpakuto actually do have spirit forms that reside within the minds of their Shinigami, but they never actively fight for their wielders and generally use Shikai/Bankai instead.
Weapon Twirling: The third seat of squad 8 tries to intimidate Chad with some quick swordplay, and just gets punched in the face.
We Are as Mayflies: Soul Reapers and Hollows (and for that matter ordinary Soul Society civilians) live vastly longer than humans. But it's a bit of a subversion, since they're what humans might become after dying.
We Will Meet Again: In anime episode #141 the Arrancar tell this to their Soul Reaper opponents and in episode 322 Kageroza Inaba says it to Ichigo.
Wham Line: The manga sports several of these. See trope page for examples.
White Mask of Doom: Hollowfication is the process by which a spirit's heart is transformed into a pale mask that covers the face. As a result, hollows wear them and Hollowfied shinigami such as the Vaizards or Ichigo can also pull on a mask when using their hollow powers.
Whole Episode Flashback: The anime is fond of these, partially because the manga itself toys with them. There are even entire flashback arcs.
Wrecked Weapon: Kubo very often uses the breaking of a weapon to signify the owner's defeat.
Wretched Hive: Districts 50-80 of Soul Society are the subject of ongoing research about the massive drop in standards of living compared to Districts 1-49. In particular, Districts 59+ have been so poverty stricken there's been no instance of any dweller possessing shoes for 550 years.
Orihime and Ishida, so, so much. Just see the page example.
In a meta example: Tite Kubo keeps doing it to the readers.
Year Inside, Hour Outside: The "density of time" within the Precipice World - which acts as the primary passage between Soul Society and the real world - is 2,000 times higher (e.g. 2,000 years inside = 1 year outside), which made the place a useful prison in the past. It was used by Ichigo and his dad to compress 2,000 hours (approx. 3 months) of Training from Hell into a single hour, in order to power him up for the final confrontation with Aizen.
You Are Already Dead: Happens pretty often, but a good example is when Aizen attacks Hitsugaya in the council chamber
You Monster!: Loly to Orihime of all people. Of course, this can be explained because Loly's an Ungrateful Bitch. Lilynette says something similar to Ukitake when he dispels her cero with his bare hand.
You Never Asked: Subverted. Urahara appears to be this until Ichigo eventually reveals (to the reader) during a moment of inner musing that Urahara never reveals information even when directly asked.
Subverted in episode 36. After Ganju grabs Hanataro and escapes, Ichigo tells Kenpachi Zaraki that he can't let him pass through to pursue them. Kenpachi tells him that he's not interested in the others: he's just there to fight Ichigo. And what a battle it is.
In episode 54 Ichigo faces off against three Soul Reaper lieutenants and Captain Kuchiki so Renji can get away with Rukia.
In episode 154 the Arrancar Dordonii repays a debt of honor to Ichigo by fighting Rudbornn Chelute and the Exequias to give Ichigo and Nel time to escape.
In episode 319 Yoruichi holds off the Reigei so Ichigo and Rukia can escape through the Senkaimon gate.
Kensei does this to several Menos Grande during the VisoredsBig Damn Heroes moment. With his bare fists.
In the manga Yammy does this to a servant who was tending to his newly healed arm. He decided to test his arm's strength by slamming his fist down on the servant's head causing it to splatter into a bloody mess. In the anime, due to censorship, it was changed to him hitting the servant with his arm causing her to smash against the wall which kills her instantly.
Zerg Rush: In Chapter 511, the Soldats rampage through the remains of the Seireitei in droves, slaughtering the red shirts along the way.