This is a list of characters who are essentially gender reversed versions of pre-existing characters. In addition to straight counter-parts, includes alternate reality versions, cross-company ersatz versions, legacy mantles, and in-continuity gender swaps.
(Earth-0 version and "Claire Kent" version) From Superman and Superboy.
From Superman (Earth-2).
From Batman.
From Batman.
From Batman, Earth-2.
From Batman.
From Tim Drake (as Robin) and Batman (as Batgirl).
From Aquaman.
From Martian Manhunter.
From Hawkman.
From Captain Atom.
From Captain Marvel and Black Adam.
From Wonder Woman.
From Riddler.
(Earth-0 version and "Ame-Comi Girls" version) From Joker.
From Green Lantern. (Non-Earth female Green Lanterns not included on list.)
From Green Lantern. (Non-Earth Star Sapphires not included on list.)
From Starman & Star-Spangled Kid.
From the Flash and Johnny Quick.
From Steel.
From Black Lightning.
From Bulletman.
From Bulletman.
From Booster Gold.
From Blue Beetle.
From Metamorpho.
From Metamorpho.
From Charles Xavier.
From Magneto.
From Magneto.
From Spider-Man (arguably).
From Ultimate Spider-Man.
From Spider-Man.
("Spider-Island" version, "Spider-Gal", and "Mangaverse" version, "Spider-Girl") From Spider-Man. (Other female Spider-empowered New Yorkers during "Spider-Island" not included on list.)
(Female "Ame-Comi Girls" version, "Empress Darkseid") From Darkseid.
(Gynoid "Ame-Comi Girls" version, "Wombworld") From Warworld.
From Metron.
From Lady Deathstrike.
(Gynoid "Ame-Comi Girls" version) From Manhunters.
From Starfire. (Non-royal tamaraneans not included on list.)
(Male humanoid version) From Carol Ferris.
From Omni-Man.
From Sinestro. (Other female Yellow Lanterns not included on list.)
From Spawn (Al Simmons)(temporarily).
From Spawn (Al Simmons).
From Fantomex.
From Spawn (Al Simmons).
From Witchblade (arguably, her male counterpart but with different powers).
(Female "Ame-Comi Girls" version) From Black Manta.
From Superman (with Lois Lane).
From Doctor Fate.
(Gynoid "Ame-Comi Girls" version) From Parademons.
From Don Allen (simultaneous introduction).
From Dawn Allen (simultaneous introduction).
From Zan (simultaneous introduction).
From Jayna (simultaneous introduction).
From Northstar (simultaneous introduction).
From Aurora (simultaneous introduction).
("Exiles" version) From Sasquatch.
From Mystique.
From Rogue (with Gambit).
From Dr. Doom (with unknown).
From Blackhawk.
From the Thing.
From Brit.
From Captain Marvel and Quasar.
From Nova. (Non-Earth female Nova Corps members not included on list.)
From Nova. (Non-Earth female Nova Corps members not included on list.)
From Super-Skrull.
From Geo-Force.
From Ravager & Deathstroke.
From Dr. Strange (arguably).
From Guardian.
From Wolverine (arguably).
From Romulus & Wolverine.
From Black Panther.
From Banshee.
("New 52" version) From Black Banshee.
From Bigby Wolf (with Snow White).
From Bigby Wolf (with Snow White).
From Bigby Wolf (with Snow White).
From Cyclops (with Emma Frost).
From Nightcrawler (with Scarlet Witch).
From Punisher (arguably).
From Kato (with unknown).
From Winter Soldier & Nomad.
From Ant-Man (arguably) & Giant Man (as Giant-Girl in "Marvel Adventures").
From Wasp (temporarily).
From Power Girl.
From Galactus.
From Hardware.
From Crimson Avenger (Lee Walter Travis).
From Hela (temporarily).
From Negative Man.
From Spider-Man (as Dusk, in "Spider-Man: Identity Crisis").
From Speedy (Roy Harper) & Green Arrow.
(As "Ronin") From Echo (as "Ronin").
From Frankenstein, agent of S.H.A.D.E.
From Multiple Man (Ersatz version).
From Dracula (I guess; this is the only vampire I'm putting on this list though).
