User possesses massive reserves of life energy, which also acts as a reliable power source that aids in their longevity, power, stamina, vitality, and healing capabilities, allowing them to withstand and survive even the most strenuous and life threatening circumstances.
Users of Spirit, Demon, and Sacred Energy (YuYu Hakusho)
Asura (Asura's Wrath) possesses the Mantra affinity of Wrath, allowing him to increase his Mantra output the more rage he builds up. However, this tends to put a massive strain on his body.
Ichigo Kurosaki (Bleach) has tremendous levels of Reiryoku, well beyond most other Shinigami...
...and upon master his potential, has levels of Reiryoku unrivalled by almost anyone.
Kenpachi Zaraki's (Bleach) immense Reiryoku.
Genryūsai Shigekuni Yamamoto (Bleach) possesses such an exceedingly amount of Reiryoku, that he can paralyze weaker Shinigami by looking at them.
Coyote Starrk's (Bleach) Reiryoku was so powerful and uncontrolled, lesser Hollows died from simply being in his presence.
Tier Harribel (Bleach) manifesting her huge Reiryoku.
As one of the oldest Shinigami there is, Ichibē Hyōsube (Bleach) possesses exceeding amounts of Reiryoku.
As the first and strongest Quincy, Yhwach (Bleach) possesses immense amounts of Reiryoku.
As the heart of the Soul King, Gerard Valkyrie (Bleach) possesses immeasurable amounts of Reiryoku.
Even sealed and crippled, the Soul King's (Bleach) Reiryoku is described by Yhwach as "an excess of power".
Already very powerful, Sōsuke Aizen (Bleach) gained even greater amounts of Reiryoku thanks to the Hōgyoku.
Goku (Dragon Ball series) possesses incredible reserves of ki energy, which can be augmented by his Kaio-ken technique and various Super Saiyan transformations...
...and in his Ultra Instinct form, Goku's Ki surpassess even the strongest of gods.
Jiren (Dragon Ball Super) is described to possess unthinkably colossal ki energy, able to erect a powerful barrier to defend against standard ki attacks, and even shake the entire World of Void, which has been stated to be of infinite size.
Jiren (Dragon Ball Super) possesses ki so immense that he is able to generate and unleash so much of it after being greatly wounded and still cause the World of Void to tremble.
Broly (Dragon Ball Super) possesses an incomparable amount of Ki energy, possibly surpassing even the likes of Jiren.
Golden Frieza (Dragon Ball Super) manifesting his immense amounts of Ki energy.
As a result of his intense training over the years, Sairaorg Bael (Highschool DxD) has massive amount of life-force (touki), at full power he took on attacks from a magic user, holy-demonic sword, and holy sword, but still came out victorious.
As an Uzumaki and a reincarnation of Asura Ōtsutsuki, Naruto Uzumaki possesses massive reserves of Yang-based Chakra, which was increased even further when he received chakra from the other tailed beasts and Hagoromo Ōtsutsuki Six Path Yang Chakra.
As an Uchiha and a reincarnation of Indra Ōtsutsuki, Sasuke Uchiha (Naruto) possesses immense reserves of Yin-based chakra which is vastly augmented by transplanting Itachi's Mangekyo Sharingan and receiveing Hagoromo's Six Path Yin Chakra.
Kaguya Ōtsutsuki (Naruto) possesses even bigger chakra reserves than the Ten-Tails, whose own chakra reserves were specifically described as immeasurable.
Hagoromo Otsutsuki (Naruto) was born inherited portion of his mother's godlike chakra which is powerful enough to dominate the Six Realms via his Rinnegan.
Indra Otsutsuki (Naruto) inherited the spiritual half of his father's Six Path Chakra that grants him tremendous Yin-based Chakra and the Sharingan.
Asura Otsutsuki (Naruto) inherited the physical half of his father's Six Path Chakra, granting tremendous Yang-based chakra which contributes to his superhuman vitality.
Jaune Arc (RWBY) has massive reserves of Aura, allowing him to completely refill an injured Weiss' without worrying about depleting his own.
Yusuke Urameshi (YuYu Hakusho) possesses vasts amounts of Spirit Energy. When he integrated Genkai's Spirit Wave Orb in his body, his reserves and power increased exponentially.