Bleach's story, while not a true isekai series, has some elements of the genre to it. Hero Ichigo Kurosaki explores worlds beyond his ordinary home of Karakura Town, was once an average high schooler who cared mostly about homework and, even after he journeyed to the incredible Soul Society, he would always consider Karakura Town his home.
Even more remarkably, this small city is more than just a "starter town" for the hero's quest. Karakura Town is actually home to many spiritual beings of all kinds, and it often acts as a hiding place or a refuge for those who don't want to be found. For the spiritually aware, Karakura Town is like a central meeting ground for ravenous Hollows, disgraced Soul Reapers and more.
Karakura Town is the Ultimate Hiding Place for Soul Society Rejects
More than one rogue party has fled to Karakura Town to escape justice or their enemies. Over a century ago, Kisuke Urahara delved deep into the mysteries of Soul Reapers and Hollows, and his forbidden research was stolen as a part of Sosuke Aizen's master plan. Aizen framed Kisuke for the crime of morphing nine Captains and Lieutenants into the Visoreds, so he fled to Karakura Town to hide. Despite Soul Society having plenty of remote corners, only the seemingly mundane Karakura Town could truly hide him from twisted justice. Kisuke set up a candy store called Urahara Shoten, but of course, he did more than sling lollipops.
Kisuke continued his research in the back rooms of his shop, and used it as a front for his true purpose: to train someone who could help him take down Aizen for good. In Bleach's main story, Kisuke quickly became an ally of both Rukia Kuchiki and Ichigo Kurosaki, eventually teaching Ichigo in the vast training arena below Urahara Shoten. No other Karakura Town resident was any the wiser.
Yoruichi was also a rogue Soul Reaper residing in Karakura Town, and it was she who helped Kisuke escape the judgement of Central 46. Aiding a branded criminal like Kisuke made Yoruichi an outlaw too, but to her, it was worth it, and she had no qualms with moving to Karakura Town and laying low for the next handful of decades. This means that by the time Ichigo was ready to go rescue Rukia, Yoruichi was on hand to act as a tour guide and escort Ichigo's party through the Dangai.
Yet another party uses Karakura Town as a hiding place: the Visoreds. Like Kisuke, they were cursed by Aizen's schemes, and were ousted from Soul Society because of them. In fact, Central 46 wanted them dead, so they banded together and chose an abandoned warehouse in Karakura Town as their HQ. The Visoreds bided their time in there, and when Ichigo began to struggle with his inner Hollow, he approached the Visoreds and passed through the barrier that Hachigen Ushida had placed around the warehouse. Orihime Inoue visited that warehouse at some point, too.
Lastly, this town is the hiding place of the last human Quincy, including the Ishida family and, in the recent past, Masaki Kurosaki, Ichigo's mother. Masaki nearly lost her life and her Quincy powers when Aizen's custom-made Hollow attacked, but Isshin Shiba stepped in and saved her life. Meanwhile, Ryuken Ishida tried to live as an ordinary human, but his son Uryu trained with his grandfather Soken to become a proper Quincy, right there in Karakura Town.
Karakura Town Is Bleach's Spiritual Battlefield
Some of the most explosive battles in Bleach take place in Soul Society, like Ichigo's final duel with Captain Byakuya Kuchiki, or the first battle against the Espadas in Hueco Mundo. But Karakura Town is the setting for many of Bleach's most emotional and consequential fight scenes of all. In the very first episode, Ichigo and Rukia faced a Hollow called Fishbone-D in Ichigo's own neighborhood, and Rukia set the entire plot into motion when she granted her powers to Ichigo. For another handful of episodes, Ichigo would roam Karakura Town with Rukia, slaying Hollows and learning more about Soul Reaping. He even found a Jibakurei — a chained soul that was mutating into a Hollow. Such things are only found in the world of the living.
Ichigo also teamed up with his classmate, the Quincy archer Uryu Ishida, and fought many Hollows with him in the series' first season, all around Karakura Town. The first on-screen Menos Grande appeared during this time, too. Later, after Ichigo returned from the Soul Society, Grand Fisher arrived as an Arrancar, and Isshin Kurosaki leaped into action. Grand Fisher had been terrorizing Karakura Town for over 50 years, but Isshin ended his rampage at last by slicing him in half.
Finally, Karakura Town was the setting for the final fight against Sosuke Aizen, including a battle that took place in a proxy version of the town. The three traitor Captains and the top Espadas faced the Soul Reapers in battle, and at some point, Aizen actually made his way to the real Karakura Town, which had been relocated to Soul Society, along with all its residents. Ichigo's classmates Keigo and Tatsuki laid eyes on Soul Reapers and Hollows for the first time during these events.