And of course you've got two Hanks running around (Pym of The Avengers and McCoy of the X-Men). And working together in the Secret Avengers, for more name-based confusions since they both fill the scientist role and the team is on a first name basis.
Beast: Wait, he gets to be "Pym," I'm just "Beast"?
Iron Man: You're both named Hank! I have bigger problems!
In a X-Men/Star Trek: The Original Series crossover, Nurse Chapel asks for "Dr McCoy?" The Beast referred to this at least once (outside the crossover), saying that whenever addressed as "Dr. McCoy, he felt the urge to say, "He's dead, Jim!"
They also DO have 2 Steves - Steve Rogers and Stephen Strange. Fortunately, while Captain America is occasionally called Steve, it's very rare for anyone to refer to Doctor Strange by his first name. And when they do, it's always Stephen, not Steve.
Incidentally, Marvel refuses to have two active super-heroes by the same name, in two separate collections but in the same universe. They can have, say, the Chameleon impersonating Spider-Man in his series, or a new Captain America while Steve Rogers cannot use the shield. However: When Jim Starlin wanted to resurrect Adam Warlock, the Warlock from the New Mutants had to go — and was killed in his own series. Similarly, the return of "the man called Nova" (Richard Rider) meant that the girl called Nova (Frankie Raye, herald of Galactus) was to be killed. Silly, because like many above examples, not only were the two Warlocks not related in anyway, they both had enemies called The Magus, who also were not related in anyway other than name. Although the New Mutants Warlock was named so as a homage to Adam Warlock, hence why he also had a villain named the Magus. To further the point. Adam Warlock's Magus was a possible future incarnation of himself. New Mutants' Magus is the father of their Warlock and its their custom for the child to kill the father and then become the new Magus.
X-Man Robert "Bobby" Drake aka Iceman and New Mutant Roberto "Bobby" Da Costa aka Sunspot.
Young X-Man Hope Abbott aka Trance and Hope the Mutant Messiah raised in exile by Cable.
Piotr Rasputin (who is often addressed as "Peter", "Pete" or "Petey") aka Colossus and Peter "Pete" Wisdom. This would not be particularly notable (the X-Books have Loads and Loads of Characters, and Wisdom never uses his full name anyway) except a) they spent a fair amount of time in the same title and b) both of them have dated Kitty Pryde. During the time when they were both on Excalibur, Colossus was generally addressed as "Piotr" or by his code-name. The two also share the name with the Marvel Universe's Peter Parker and the Trapster, formerly known as Paste-Pot Pete.
When Kitty Pryde started dating Peter Quill, aka Star-Lord, one of the character commented that she only ever dated Peters.
Early in The Amazing Spider-Man, Peter Parker dated Betty Brant while his classmate Liz Allan made a play for him. Both girls were called pet forms of the name Elizabeth. Meanwhile in The Incredible Hulk, Bruce Banner's love interest was Betty Ross; and Betty (or Betsy) Ross had also been the name of a Captain America supporting character in the Golden Age, who for a time became his sidekick, the first Golden Girl. Betty Brant worked as secretary to J. Jonah Jameson, a position where after her wedding to Ned Leeds she was replaced by the rather similar sounding Gloria Grant.
There's something about "Mary" for Peter Parker: His late mother was called Mary Parker, while his Aunt May bears a name that can be a variation of "Mary". Peter went on to date and eventually marry Mary Jane Watson, the niece of Aunt May's best friend, Anna May Watson (and in the New Testament, Anna is the mother of Mary). It later was revealed that MJ's mother was called Madeline (a French variant of Mary Magdalene). And when Peter and Mary Jane had a daughter, they decided to call her May.
Penance from Generation X came back after Speedball had gone emocore and called himself Penance as well. Nowadays she's called Hollow.
In New X-Men: Academy X, there are technically two Joshes in the New Mutants squad - Joshua Guthrie (Icarus) and Josh Foley (Elixir). However, earlier in Uncanny X-Men, Josh Guthrie decided to go by "Jay" because he feels that after his girlfriend died his old name should be left in his past too.
There is a "Laurie" and a "Laura" in New X-Men: Childhood's End, but one is dead and one can't die.
X-Men used an aversion of this as part of Jubilee's backstory — her parents were murdered because her father happened to have the same name as another doctor who was involved with organised crime.
Kurt Wagner aka Nightcrawler and Juggernaut's father Kurt Marko. Nathan Christopher Charles Summers aka Cable, named after his grandfathers Nathaniel Essex, Christopher Summers, and Charles Xavier.
Victor Creed aka Sabretooth and Victor Borkowski aka Anole.
Brian Braddock aka Captain Britain and Charles's father Brian Xavier.
The "no shared codenames" rule was abandoned altogether in the 2010s with the two Hawkeyes. Kate Bishop took on the "Hawkeye" identity in Young Avengers at a time when Clint Barton was believed to be dead (and very briefly actually was). However, after he made his resurrection public he gave her his blessing to continue using the identity with no "Young" or "Ms."/"Lady"/"Woman" modifier, and the two have teamed up regularly.
And this continued with Peter Parker and Miles Morales sharing the name Spider-Man, Steve Rogers and Sam Wilson sharing the name Captain America.
The Marvel Universe also has two Gladiators - Kallark, the Majestor of the Shi'ar Empire, and the Daredevil villain Melvin Potter.
Make that at least two male Captains Marvel (Mar-Vell and his son Genis-Vell - three if you count Skrull impostor Khn'nr) and three female ones (Monica Rambeau, Phyla-Vell, and now Carol Danvers). And that is not counting the Golden Age Captain Marvel (Billy Batson) originally published by Fawcett and the self-splitting android Captain Marvel published by M. F. Enterprises in 1966, or the Amalgam Comics character that merged Batson and Mar-Vell into one, but retained the Captain Marvel name.
On Ms. Marvels we have the above-mentioned Carol Danvers, as well as Sharon Ventura, Karla Sofen and Kamala Khan.
Speaking of which, Sharon Ventura shares her first name with Sharon Carter, aka Agent 13.
In Marvel's MC-2 Universe, the Felicia Hardy aka the Black Cat and Eugene "Flash" Thompson got married, had two children and got divorced. One child each ended up with a parent, Felicity Hardy living with her mother, Gene Thompson with his father.
The Iron Man villains Crimson Dynamo (introduced 1963) and Whiplash (introduced 2009) are both named "Anton Vanko," but are otherwise unrelated.
Marvel also has Sam Wilson (The Falcon), Sam Guthrie (Cannonball), Sam Alexander (Nova) and Sam Chung (Blindspot). Lampshaded in a Nova issue where Captain America calls the Alexander household looking for Sam, and Nova assumes that he must have mistakenly called while looking for Sam Wilson.
In the series Alias (no relation to the TV series), the main character, Jessica Jones, had a run-in with another Jessica, Jessica Drew. Both Jessicas were former superheroes turned private investigators, and Brian Bendis has stated that he created Jones as an Expy of Drew after he was denied permission to use the latter. This is a plot point, because another character, Mattie Franklin (former superhero turned junkie) broke into Jones' office, thinking it belonged to Drew, whom she knew and was looking for.
It also may be some Lampshade Hanging, as Brian Michael Bendis had actually wanted to write the series about Jessica Drew, but Marvel didn't want to risk her on a MAX title. So instead, the somewhat similar Jessica Jones was created and retconned into the Marvel Universe.
In Marvel Comics, Cain Marko is the Juggernaut; William Baker, alias Flint Marko, is the Sandman; Michael Marko is "Man Mountain" Marko. This wouldn't be so unusual if the last name weren't so uncommon, really.
Any two characters who share a surname will always turn out to be related — though rarely will either character be created with that intention. This often occurs with characters who were originally published by different companies that were eventually assimilated by the Borg acquired by DC. They've even done it with a Sanders and a Saunders, who became distant cousins or something.
The major exception to this rule is the existance of both Carter Hall and Hank Hall, who not only share the same surname but also have similar superhero aliases, Hawkman and Hawk, respectively. They have yet to be retroactively related to one another.
In his first appearance, Harvey "Two-Face" Dent was named Harvey Kent. This was changed to avoid suggesting a familial connection to that otherKent gentleman.
This became a plot point in the "Mr. and Mrs. Superman" story in Superman Family that featured the wedding of the Earth-2 Bruce Wayne and Selina Kyle. One of the wedding guests was Harvey Kent of Earth-2 (who stayed reformed, unlike the Earth-1 Two-Face), with Lois and Clark investigating a potential mob hit on "someone named 'Kent'."
Chuck Dixon actually wanted to make Dinah Drake, the original Black Canary, the great-aunt of Tim Drake, the third Robin, but DC Editorial shot it down. Pity, given that it was more plausible than some of the other examples: both Drake families are, canonically, long-time Gotham residents.
Jason Todd (the second Robin) shares a first name with Jason Garrick (the first The Flash), Jason Bard (private investigator and occasional love interest to Barbara Gordon) and Jason Blood (the demon Etrigan), among others.
The real name of D-list villain The Cavalier is Mortimer Drake. Since he's fairly obscure, DC probably doesn't have to worry about people wondering whether or not he's related to Tim.
In the Batman family, there are two Harvey's; Harvey "Two-Face" Dent and Detective Harvey Bullock.
There are also two Victor's: Victor Fries and Victor Zsasz. Three if you count the first The Question. Vic Sage's birth name is Charles Victor Szasz.
Originally, the name "Starfire" belonged to a Russian superhero, but over time he fell into obscurity. The name then became associated with the Teen Titans character. When the original was used again later, his name had changed to Red Star.
And there's another DC's Starfire, a swordswoman. Lampshaded by Booster Gold in the mini-series Time Masters: Vanishing Point, when he meets this Starfire and comment on the coincidence between her name and Koriand'r's.
In the Golden Age, DC had a hamfisted private eye Slam Bradley and his goofy sidekick Shorty Morgan. While Bradley's real name was revealed as Sam early on, it wasn't until decades later that Shorty Morgan was named Samuel as well, justifying the need for nicknames.
Cassandra Cain and Cassandra Sandsmark filled the roles of Batgirl and Wonder Girl, respectively. While Wonder Girl is still the same person, the mantle of Batgirl was passed to Stephanie Brown.
For added confusion, we have Cassandra Cain as Batgirl/Black Bat and Kate Kane as Batwoman.
Cassie Sandsmark was on the Young Justice team with Cissie Jones-King & a girl called Suzee. They were all blonde. Meanwhile Marvel had already had a blonde teen character named Cassie Lang. This was called out by fans as a bunch of girl characters too similar. Eventually Cissie quit & Suzee started going by her real name, Greta.
Speaking of Batgirl, Barbara Gordon, the original Batgirl, shares the same name with Barbara Minerva, also known as Cheetah, Wonder Woman's Archenemy.
Aquaman's real name is Arthur Curry; at one point, the comic starred a different Arthur Curry/Aquaman, a teenager with no connection to Atlantis. It turns out this Arthur is the original's cousin on his father's side, deliberately named after him.
With Wonder Woman having such strong relations with the Greek pantheon, it was only a matter of time before the Titans (Oceanus, Hyperion, Coeus, Cronus, Crius and Iapetus and the females Mnemosyne, Tethys, Theia, Phoebe, Rhea, and Themis) were included as well. But DC has their own Titans, so this other group was named the "Titans of Myth". And if you think that's confusing, it's even more for Tria, who has been a member of both.
DC Comics has had multiple characters using the Manhunter name, often simultaneously, and that's not even taking the android antagonists into consideration. You had Mark Shaw, Chase Lawler, Kate Spencer, and several clones of Paul Kirk, for starters. But the most egregious example of this came in an issue of All-Star Squadron, where the Paul Kirk version (created in DC's Adventure Comics) runs into the Dan Richards version (an import from DC's acquisition of the Quality lineup of heroes) and they argue over who was first to take the name. Note that they originally appeared a month apart in 1942 from two different companies and never met until this retconned adventure.
DC has two Artemis': The Amazon "Artemis" and the C-list villain "Artemis Crock" better known for her Young Justice counterpart.
For April Fools' Day in 2013, the DC Comics website altered the profiles of Superman and Batman on their character pages; making use of the similar names of their mothers. Martha Wayne survived being shot and signed guardianship of Bruce to the butler when she was put into the Witness Protection Program. She was sent to Smallville, married John Kent and became the couple who found and raised the baby who would become Superman. This would make Batman and Superman brothers. The prank was so subtle, that DC Comics had to point it out the day after.
Part of the reason people don't know there are two Black Canary's is due to this. They're a mother and daughter duo both named "Dinah". They wear the exact same costume and the only difference, until the mid-to-late 90s, was the original had long black hair while the daughter has black Boyish Short Hair. Neither of those differences are noticeable as they wore blonde wigs as superheroes, though the second Dinah eventually grew out her hair and dyed it blonde. DC sometimes changes the spelling of the first Dinah's names however they usually use her maiden name "Dinah Drake", while the post-Crisis Canary is "Dinah Lance".
Bizzarely, there are two Garfields in the DCU, Garfield Logan, also known as Beast Boy/Changeling of Teen Titans fame, and Garfield Lynns, a.k.a Firefly, one of Batman's several rogues. None of them is a lazy fat cat, although one of them could easily transform into one.
Averted in the Universe as a whole, but played straight in story basis in the Mickey Mouse Comic Universe. Since is also a Mythology Gag, the name Mortimer is used a lot. But, the Mortimers never interact and are keep in the boundaries of the story been told at the same time.
The Plain Janes: The five lead characters are all named Jane. They have adjectives attached to help determine who is who. Ex: Theatre Jane.
Pearls Before Swine has its endless supply of "Bobs" in addition to Neighbor Bob and the fictitious Angry Bob. Stephan Pastis wrote in commentary that "Bob" is a funny name. It has two "b"'s ("b" is a funny sounding letter), it's a palindrome, and a verb.
The Adventures of Tintin has two detectives that look nearly identical and are named "Thomson" and "Thompson" (Dupond and Dupont in the original French). This also a case of No Name Given, as neither has a first name ever mentioned that could be used to tell them apart.
Though in a straight example, a third character coincidentally carrying the same name, Allan Thompson, effectively got his surname erased in the English translation to avoid undue confusion.
Inverted in Amelia Rules! series, the concept of the "Legion of Steves" being a group of people all named Steve.
Scott Pilgrim has a second character named Scott, who is always referred to by the rest of the cast as "Other Scott". Regular Scott also has a tendency to mix up people with similar names, and for most of the second book confuses Lucas Lee (the villain), Lucas "Crash" Wilson (a member of the series' recurring "Quirky Miniboss Squad") and Luke Wilson (the actor) as well as when referring to Todd Ingram (the evil vegan ex) says "Todd Rundgren or whatever is psychic!"
There's also kind of a weird subversion to this principle at the end of volume 2. Scott is telling Ramona about how his ex-girlfriend Envy broke up with him and started dating some guy named Todd. Ramona says, off-handedly, "I dated a Todd once." Scott sarcastically replies, "Great story! Maybe they're the same guy!" They are.
In Y: The Last Man Yorick sleeps with a woman with the same name as his fiancee Beth. As a result Beth II (or Other Beth) has a child she names Beth Junior. Eventually all three meet up in Paris.
Hero: "I'm sorry Beth, but Beth has a right to know about... Beth."
Beth 2: "I know it would have probably been easier if I'd named her Betty or Elizabeth, but I've never gotten along with chicks who go by the variations, have you?"
Most of José Carioca's various relatives are also named José (family reunions must be confusing). Fortunately, they all have unique last names that they can be identified by. For extra fun, José's rival (Who's not related to him) is also named José. This is probably because it's a stereotypical name for a Brazilian.
Peanuts had two characters named Patty. The original Patty dates from the first strip, and wore a checkered dress and bow. The more memorable character was the later appearing Peppermint Patty. One would assume the Pun necessitated the exception, but Original Patty disappeared by the mid '70s. (Worth pointing out, too, is that Original Patty was Charlie Brown's very first antagonist in the first-ever Peanuts strip (when CB was something of a Jerk Ass, not the lovable emo kid we know and love), while Peppermint Patty was always portrayed as being madly and desperately in love with the clueless Chuck.)
Played with in Fables. Jack Horner, Jack of the Tales, Jack o' Lantern, Jack Frost, Jack B. Nimble, Jack B. Quick, and Jack Giantslayer are all aliases for the same person. Every last fable about someone called Jack, with the exceptions of Jack Spratt, Jack Ketch and Jack Frost (in The Great Fables Crossover), seems to turn out to be him, and he magically becomes the central character of any story he's in, to such a degree they had to boot him out of the comic.
Three Mikes in the coming-of-age book set in The '80s, The Copybook Tales.
In an Americomics Blue Bulleteer oneshot, the heroine known as the Blue Bulleteer crosses paths with a hero also calling himself the Blue Bulleteer. Neither has ever heard of the other. She's had the name for longer, but he had it patented. By the end of the story they seem to have reconciled the fact that they operate under the same, because they both keep using it afterwards.
In X-Force, team director/owner Spike Freeman and team member the Spike shared a name. Lampshaded when Freeman says he really likes the Spike, and not just because of his name. This is pretty much the only time it comes up; the two share very little screen time and never even really talk to each other. Whereas the Spike was a big deal towards the end of the team's run as X-Force, Spike Freeman only became a major character after the Spike died and the book was relaunched as X-Statix.
Averted in British girls' comic Bunty, whose main strip The Four Marys was Exactly What It Says on the Tin. The girls went by nicknames based on their surname - "Raddy" (Mary Radleigh), "Cotty" (Mary Cotter), "Simpy" (Mary Simpson) and "Fieldy" (Mary Field.)
In the Judge Dredd comics there have been two completely separate characters with the incredibly specific name "Spikes 'Harvey' Rotten", and in addition to sharing the same name, both were reputed to be ruthless bikers and part of a biker gang called "The Muties." The only thing that really sets them apart is their physical appearance. The first Spikes "Harvey" Rotten was a minor character who died in an illegal street race through Mega-City One; the second accompanied Dredd on his trek to Mega-City Two during the "Cursed Earth" story arc.
James "Jim" Gordon married Barbara Kean Gordon. They had two kids, James and Barbara Gordon.
Deliberately averted with various minor characters in The Walking Dead, as it would really stretch suspension of disbelief to not have any repeating names among all the random groups of survivors.
In Brazilian Portuguese translation, both Jack Horner and Hansel are named João. Justified for two reasons: 1- That's how the original characters (from the fairy tales they're based on) have been traditionally known in Brazil for centuries; 2- Both translations are accurate, as Jack and Hansel are local short forms for variations of the same name (English: Jack–>John; German: Hansel–>Hans–>Johannes) and João is the Portuguese variation of the name.
There are also two Cybertronians named Tankor, they are known as "Tall Tankor" and "Fat Tankor," though not to former's face.
In Rat Queens, the Four Daves are a party of four men, all of them named Dave. Others refer to them by race ("Orc Dave", "Smidgeon Dave", etc.), but within the group they just call each other "Dave".
Referenced in The Wicked + The Divine when discussing the mythology. There's only one Baal in this recurrence, but until Issue #4 they don't know which Baal he is (it's Baal Hadad, by the way). There's also Tara, who might be the Hindu Goddess or a Boddhisatva.
In Ms. Tree, the heroine, her late husband and his son (her stepson) all share the same name: Michael Tree. To avoid confusion (both in-universe and out), Ms. Tree is usually referred to as Michael, her late husband as Mike, and his son as Mike, Jr.