Joshua Foley/Elixir (Marvel Comics) can bring people back from dead including himself.
Christopher Muse/Triage (Marvel Comics)
Morgan le Fay (Marvel Comics) has been 'killed' more times and in more varied ways than any other villain in the Marvel Universe. Despite this, she has survived each and every single time, most often appearing seconds later after her 'death' seemingly unharmed.
Due to the Immortality Curse placed on him by the Demon King, Meliodas (Nanatsu no Taizai) is able to return to life after dying in exchange for his personality to degrade to his old evil being.
Phantom (Marchen Awakens Romance) will always come back to life as long as the Zombie Tattoo curse remains on his body.
Orichalcos Gigas (Yu-Gi-Oh!) is one of the few monsters that resurrects itself when killed.
Mitchell Shelley/Resurrection Man (DC Comics)
Ichibē Hyōsube (Bleach) is resurrected due to Ichigo calling his name.
Yhwach (Bleach) can use "The Almighty" to freely change any future in which he dies into one in which he survives.
The Ajins (Ajin: Demi-Human) most significant trait is their ability to regenerate their bodies upon their deaths, coming back to life.
The Totem of Undying (Minecraft) in action as it revives the user after they receive fatal damage.
Kenny McCormick (South Park) is always reborn because of cult’s curse.
Henry Morgan (Forever)
Utsuro (Gintama) resurrecting himself from a severed arm after Umibozu killed his "main" body, which used up a huge amount of Altana.
SCP-607 - Dorian the Grey Cat (SCP Foundation)
Deathstroke's (DC Comics) healing factor is so advanced...
...that he can regenerate and resurrect from a shot to the head.