Every month, among the dozens of comics featuring Marvel and DC characters, there are always a few that feature a character that has a lineage going back so far as to put them in the public domain. Every year, new works of literature lose their copyright protection and become free to use for any daring creator.

RELATED: 5 Great Public Domain Superheroes (& 5 Worst)

It is a daunting chore for a creator to try to take a legendary work like the Great Gatsby and expand upon it. However, there are also the pitfalls of trademark, for while the copyright on stories might have lapsed, organizations like the one managing the estate of Robert C. Howard maintains control of the trademarks. Some characters firmly lie in the realm of the public domain, albeit with some cautious advice.

10 H.G. Wells' Time Traveler

Time Travel in Allan and the Sundered Veil

Most comic book appearances of H.G. Wells' unnamed Time Traveler from The Time Machine have been in adaptations of that book. Alan Moore did use the Time Traveler in the prose story Allan and the Sundered Veil in the first volume of League of Extraordinary Gentlemen. Many prose writers have written unofficial sequels to the Time Machine, proving how ripe it is for exploration.

RELATED: Marvel: 10 Best Time Travel Stories

In 1979, a film was made where the time traveler finds his machine used by Jack the Ripper to escape the police, incorporating yet another public domain character, albeit historical. The character is ripe for any imaginative creator to explore the ramifications of time travel. It's even possible for imaginative and fun stories to be written using the traveler and his machine.

9 Sherlock Holmes

cover detail from Sherlock Holmes 1992 comic

Sherlock Holmes is the classic detective that sets the standard for all other detectives that came after him. In Canada, all of his stories fall into the public domain, and in the United States, only The Case Book remains under copyright. According to sherlockian.net, a 26-year-old organization based in the University of Michigan, the Estate of Arthur Conan Doyle has made claims in the past, but those cases have not gone their way.

The former wife of the producer of the 1950s Sherlock Holmes television series has also made copyright claims that have been dismissed in court. Multiple people and organizations have tried to establish a trademark but failed, usually because of the objections by other claimants, all of whom have failed to establish ownership of this public domain character.

8 Cthulhu

Cthulhu from Moon Knight #191 by Jacen Burrows

The Elder God Cthulhu remains a popular boogeyman, especially for those with a Victorian affinity. Because Lovecraft died in 1937, his works are now in the public domain. However, the Cthulhu mythos has been built upon by other writers whose work is still in copyright. Any creator using the Elder God should be certain to only those aspects in Lovecraft's work.

RELATED: Lovecraft Country: 10 Cosmic Horror Games To Explore

There's also the shadow of Lovecraft's racism and anti-Semitic views. The fact that he held horrible opinions about those he deemed beneath himself remains a stain on his legacy. Any creator making use of Cthulhu and other Lovecraft creations needs to be ready to address this.

7 The Amazons

Cover detail from Odyssey of the Amazons #2

It may seem odd to find something so integral to the history of Wonder Woman to lie in the public domain. The Amazons actually existed in Greek Mythology. DC Comics has even managed to draw in much more of the mythical history of the Amazons for the comics.

Even Queen Hippolyta is up for grabs as long she is kept to those aspects detailed in the legend of Hercules. There are other queens, but all of them rule over a society of female warriors. They were not immortal, using men for procreation and raising only female children. For any creator using the mythical Amazons, research is a wise approach.

6 Dorothy & the Wizard of Oz

Dorothy of Oz by Eric Shanower

A creator wishing to invoke the public domain for their work featuring characters from Oz needs to stick to the books. Eric Shanower and Skottie Young took this approach with their 2009 series for Marvel. The main thing to avoid is the ruby slippers, unique to the 1939 MGM film.

While many reference the better known Wonderful Wizard of Oz, there are other books and characters to draw from. Thirteen sequels introduce characters like the Nome King, The Patchwork Girl, and Princess Ozma. An enterprising creator could build adventures around a magical land created over a century ago.

5 Jack the Ripper

Batman faces Jack the Ripper in Gotham by Gaslight

Historical figures, especially those whose true identities remain unknown are ripe for use in comics. Batman has faced down Jack the Ripper. In other media, the serial killer has even been a time traveler. The possibilities are endless.

RELATED: Alan Moore's 10 Best Comic Series, Ranked

An enigma like Jack the Ripper can blend with other genres and characters. Sherlock Holmes has been invoked often, but legends like Frankenstein, Dr. Jekyll, Dracula, and even modern science fiction elements like aliens can be blended into the story. All it takes is imagination, which is something comic book creators have in abundance.

4 Frankenstein's Monster

Monster of Frankenstein by Marvel Comics

Frankenstein by Mary Shelley is one of the all-time great science fiction and horror stories. Both Marvel and DC have incorporated the monster from the novel into their comics. Other companies like Dell, Archie, Electric Frankenstein, and Prize Comics have all adapted the monster to new stories.

While Marvel and DC have been the most public, with DC publishing Frankenstein, Agent of S.H.A.D.E. as recently as 2013. This doesn't preclude anyone else from crafting new stories with the character. If anything the treatment by Marvel and DC shows how versatile the character is, even after more than a century.

3 Hercules

Marvel's Hercules by John Romita Jr

Many comic fans instantly think of a version of Hercules that was a member of Marvel's Avengers. However, DC has had a version of the Greek demigod as far back as the Golden Age, being an antagonist to Wonder Woman. Erik Larsen has put the character into Savage Dragon as Herakles.

Being a mythological character, all a creator has to do is steer clear of anything identifying Hercules with the Marvel or DC versions. Being immortal, there is a lot of freedom with a character that could have evolved over two thousand years.

2 Thor

Thor from Sandman by Kelley Jones

With the Marvel films, Thor has become very well-known by the general public. However, there are numerous versions throughout comics. Neil Gaiman's Sandman had a drunken lout of a Thunder God. Walt Simonson's Ragnarok has a very different Thor from the thunder god he revitalized at Marvel. In the 1980s, Bill Willingham even had a little fun with his version of Thor in Elementals.

Norse mythology is rich with tales of Thor and his family. As with Hercules, there is room for exploring what happens with an immortal being once worshipped as a god after a millennium. A warrior God like Thor might be interesting to see explored through history. It is a delicate line to tread though with a character that has a version in the public zeitgeist.

1 Dracula

Dracula vs. Apocalypse in X-Men

In comic books, the most popular version of Dracula is by Marvel Comics, resembling the Universal Studios film version of the character. Almost every publisher has had their version of the lord of vampires. As a legend, the undead creatures are likewise free to use. Bram Stoker's titular character has been in the public domain for over fifty years.

Like with many characters in the public domain, so much can be done with the character. However, many interpretations go the route of a predatory figure. A very different path was taken by Dell Comics in 1966. While not terribly successful, it did place a descendant of the legendary vampire as a superhero. Being in the public domain means that the possibilities are endless, no matter how absurd.

NEXT: Why Deadpool Once Worked For Dracula... And Stole His Girlfriend