In certain fanfictions, a magical or spiritual artifact plays a crucial role in Ichigo getting his powers back. This artifact might be something that has a deep connection to his past or his family heritage. It could bestow upon him the energy or the knowledge needed to regain his powers. Maybe it was hidden away for a long time, waiting for the right moment to be discovered by Ichigo.
Another way Ichigo could get his powers back in fanfiction is through a magical or spiritual artifact. Maybe he discovers an ancient sword or a talisman that has the ability to restore his lost powers. This could be part of a grander plot where he has to go on a quest to find this item, facing various challenges and enemies along the way. During this journey, he might also learn more about the true nature of his powers and how they are connected to the overall 'Bleach' universe.
Deadpool got his powers through a messed-up experiment. His body was subjected to a procedure that gave him superhuman abilities, but also left him scarred and crazy.
The Hulk got his powers through a gamma radiation accident. Bruce Banner was exposed to a huge dose of gamma rays, and that's what transformed him into the Hulk when he gets angry.
Morbius gained his powers through a failed experiment aimed at curing his rare blood disease. The process transformed him into a vampire-like being with enhanced strength and other abilities.
Deadpool got his powers through a rogue experiment. A weapon program tried to give him enhanced abilities, but it went awry, resulting in his unique powers and messed-up appearance.
Kraven got his powers through a combination of genetic enhancements and intense training in the wild. He developed enhanced strength, speed, and senses.