Here is an archive of all the past top five lists I've one over the years.
I recently did a top five list of the top five supporting cast members who moved from one title to another. Now we take a look at the top five supervillains who began their comic career as a member of one hero's rogues gallery but ended up being more notable as a foe of a different superhero/superhero team.
CHARACTERS WHO DON'T REALLY COUNT
DC has a few examples of characters who began as individual threats that became just general "any superhero" threat, like Solomon Grundy (first a Green Lantern foe) and Vandal Savage (also first a Green Lantern foe). I don't think these guys really count for this list, because they really didn't become part of any one hero's rogues gallery. Same basic concept applies to Thanos and Darkseid, who very quickly became just generic "cosmic villains." I think Galactus sort of applies to that category, as well.
Lady Deathstrike debuted in the pages of Daredevil, but she didn't become a VILLAIN until she met Wolverine (even though their rivalry was also pretty silly).
Apocalypse is close to qualifying, but he started out fighting X-Factor and then, when the members of X-Factor rejoined the X-Men, he became an X-Men villain. That's not really changing rogues galleries, is it? He just followed his rogues to a new book.
The Ultra-Humanite debuted in Action Comics #13 as a Superman foe, but he has since become much better known as a Justice Society of America villain and a Power Girl foe.
Cyborg-Superman is still obviously a Superman foe (hence the name), but he also destroyed Hal Jordan's home of Coast City, so he has also become a Green Lantern Rogue...
That same visceral connection is why Major Force became a Green Lantern rogue. Dude STUFFED GREEN LANTERN'S GIRLFRIEND INTO A REFRIGERATOR!!
Silver Samurai debuted in the pages of Daredevil #111 by Steve Gerber and Bob Brown...
before Chris Claremont made him a Wolverine rogue (after Claremont first connected him to Viper in Marvel Team-Up)...
The only reason Silver Samurai isn't on the top five is that while he will always be connected to Wolverine, he's not exactly all that much of a ROGUE of Wolverine's. They work together more often than not.
Viper herself is a tricky one. I don't think she ever officially stopped being a Cap rogue, despite clearly also becoming a Wolverine rogue, so I don't think she works for this list. She is not completely associated with Wolverine. Heck, her most famous comic book appearance is still in Steranko's cap "run."