Every time Doomsday (DC) is killed, he returns from the dead immune to what previously killed him.
Whenever the Resurrection Man (DC) is killed, he returns to life with a new power that correlates in some way to his death.
After being killed by Tommy Jarvis and resurrected by a bolt of lightning, Jason Voorhees (Friday the 13th) has developed superhuman strength, near-invulnerability, accelerated healing, and virtual immortality.
Clifford Zmeck/Major Force (DC Comics) is able to revive an endless number of times growing more powerful with every death due to his connection to the quantum field.
Orichalcos Gigas (Yu-Gi-Oh!) resurrects itself every time it dies, cumulatively gaining 500 more attack points.