Phil Urich stumbled on a Green Goblin costume and got doused in the Super Serum (note, it was explicitly this — unlike the earlier Psycho Serum, this one didn't make you insane), producing the irony of a guy a lot like Peter Parker (snarky journalist Unlucky Everydude) taking on the identity of Peter's worst enemy. In the main Spider-Man series, Urich did end up suffering from mental problems and ultimately pulled a Face–Heel Turn.
In the Spider-Girl series, things went better, and he is an Honorary Uncle to the heroine, and has moonlighted as a superhero in both his Green Goblin costume and as the "Golden Goblin" (basically a Palette Swap Hobgoblin).
Also in the Spider Girl series is Normie Osborn. Following his father and grandfather, he took on the Green Goblin identity as a villain, but after conquering his demons ended up being a Redeeming Replacement for Venom (although he doesn't call himself that)- he was forcibly merged with the symbiote but managed to stay mostly sane with it and fight crime. Similarly to the irony with Urich, Normie is a friend and love interest to May Parker, despite running around in the costume of one of her father's worst enemies.
And the series has another example in Brenda Drago, Raptor, who ends up marrying Normie Osborn. She's the daughter of Blackie Drago, the second Vulture, and started out as a criminal, but then reformed and became an antihero.
The first Wraith was Brian DeWolff, a powerful psychic who had a Heel–Face Revolving Door, but is mostly remembered for attempting a Roaring Rampage of Revenge against the police department when his sister, Detective Jean DeWolff was killed, only to be immediately shot by the Scourge of the Underworld. His successor is a heroic vigilante who uses Spider-villain technology to pose as Jean's ghost.
The alternate-universe-heavy series Web Warriors, spinning out of Spider-Verse, introduced Octavia Otto, a gender- and morality-flipped version of Doc Ock who was the Token Good Teammate in an evil cabal of AU Electros and Ocks. She joined the Web Warriors and was still helping AU Spiders fight the good fight as of Spider-Geddon.
The versions of Sabretooth and Mimic that were members of the Exiles were heroes from alternate universes. However, the original Mimic isn't so bad these days.
While on his deathbed, B-List supervillain the Black Knight begged his nephew Dane Whitman to restore honor to their family legacy and to atone for his crimes. Whitman did so, becoming a heroic Black Knight still active to this day. The villainous Black Knight is also something of an inversion: he based the identity and his equipment off of his heroic ancestor, the medieval Black Knight.
Dane Whitman's debut also deconstructed the concept: when he first tried to join the Avengers, they immediately attacked him assuming him to be his villainous uncle (understandable, since he kept the full-face mask).
Carter Slade, the original Ghost Rider, is in the same boat. His descendant, Lincoln Slade, went mad and tried to rape Mockingbird multiple times before being replaced by his descendant, Hamilton Slade, who was good. But Hamilton died trying to exorcise Lincoln's spirit from his daughter, and all Ghost Riders (now usually called Phantom Riders) since have been evil. Another descendant of Carter's, J.T. Slade, went by "Hellfire" and turned out to be a double agent for Hydra.
Loki's various deaths and rebirths since the Siege are in-universe attempts to create one of these, as evil is predictable, Loki would rather die than be predictable, and that's very literal. Turns out it's not as easy as it sounds, mostly because Loki is Loki and dreadfully prone to sabotage themself.
First the evil one died in a Heroic Sacrifice and was replaced by the Kid Hero Kid!Loki. Then, just when things were looking up for him, Siege! Loki screwed the new version over from beyond the grave by trying to usurp his good name with a Cloning Gambit. This backfired, creating Agent Loki.That version then had to deal with an evil future self trying to force them back into their old ways. All this just served to create a fourth Loki shortly before Secret Wars (2015), who decided to be done with the whole label of being a hero or villain. This Loki settled on being a Wild Card, whose end goals are usually benevolent, but will occasionally play the villain role if that's the best way to get things done.
Inverted by Hawkeye 2099 in Spider-Man 2099: Exodus. While all other 2099 characters who share a name with a present day character have the same morality as their predecessor, this Hawkeye is a ruthless assassin who, apart from the purple outfit, has more in common with Bullseye. His main link to the Hawkeye legacy seems to be that he killed the original Black Widow.
