The CW's Arrow hits the milestone of 100 episodes on Wednesday, November 30th, and in that number of episodes there have been numerous characters that have come and gone. Some fan favorites became series regulars; others weaved in and out throughout the seasons.

Below, you'll find 10 of the show's best unsung heroes. The list is limited to those who didn't become regulars on the show, but who were always listed as guest stars. We all know Oliver Queen, Felicity Smoak, John Diggle, Laurel Lance, Thea Queen and company... but who else has stood out and made the biggest impact to the series over the years? Here are a few of our unappreciated favorites -- maybe a few of them will be seen or mentioned in Wednesday's centennial episode!

Nyssa

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Image via The CW

Oliver Queen's only wife to make the list, Katrina Law's Nyssa first made her way to Arrow in Season 2's "Heir to the Demon," and preceded the appearance of her famous father, Ra's al Ghul, by several episodes. A brave warrior with a past that was tied to Sara Lance's, the trained assassin always elevates any episode she appears in. Sadly, Katrina Law is currently tied to the upcoming Training Day TV series but hopefully Nyssa will still find her way to Star City again soon, especially as her sister Talia is headed to town around midseason.

Walter Steele

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Image via The CW

An early fixture of the series who married Oliver Queen's duplicitous mother Moira, audiences probably expected Walter Steele to turn out to be evil, but that's not where the show went with him. Sadly, actor Colin Salmon departed for other projects and hasn't been seen in Star City since near the end of Season 2. Walter is remembered, however, for his role in many of the show's early interesting storylines, including one that more properly brought Emily Bett Rickards' Felicity Smoak into the mix.

Lyla Michaels

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Lyla Michaels (named after the DC Comics character who is ultimately known as "Harbinger") made her way to Arrow in late Season 1 and has since proven herself to be an anchor for the show's own anchor, John Diggle. Though Diggle and Lyla -- who eventually got married -- have occasionally had their rough spots, they may have the most normal relationship in the entire series. Lyla also serves as an important connection to the ARGUS part of the Arrowverse.

(Interesting trivia: Years before Arrow, Audrey Marie Anderson starred in one of the first TV pilots worked on by Arrow Executive Producer Andrew Kreisberg).

Shado

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One of the first major Green Arrow comic book characters to appear in the flashbacks, Celina Jade's Shado may have been a lot less dangerous and cunning than her four-color counterpart, but she still has played an important part in the show's development, with her death being the fuse that lit Slade Wilson's rage as a major part of Arrow Season 2. We've seen Shado has a sister who has shown up on the series, so perhaps we will see her again at some point. The original Shado, however, is dead.

Floyd Lawton / Deadshot

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Floyd Lawton, better known as Deadshot, first came on to the Arrow scene with the third episode and paved the way for the Suicide Squad to be a part of the show. Michael Rowe's version of the character was so popular that producers ended up bringing him back on two separate occasions after Deadshot's untimely "death." While Will Smith is the big-budget Deadshot that we see in the DC Comics films, appreciation for his character still hasn't taken away from what Rowe brought to the table. Michael Rowe has since taken on a new comic book role in the Ninjak vs. the Valiant Universe web series.

Original Recipe Count Vertigo

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Arrow's second "Count Vertigo" Werner Zytle, as played by Peter Stormare, may have been a bit over the top, though he was closer to what people expected from the comics. However, it was Seth Gabel's first dealer of "Vertigo" that introduced the character to the masses with a deranged Joker-like performance coming from the Fringe and Salem actor. Count Vertigo #1 fell to his death, but his appearances on the show were among the series' early highlights.

Helena Bertinelli / The Huntress

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A vigilante who put on a proper mask before Oliver Queen even did, the Huntress served as a reminder to Oliver about what would happen if his darker impulses went unchecked. The current direction of the series would be the perfect time for us to see Jessica de Gouw's character of Helena Bertinelli again; sadly, there have been no announcements as of yet about her return.

Anatoly Knyazev

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Admit it: You were excited about the Russian flashbacks on Arrow because it meant we'd get to see more of David Nykl's Anatoly Knyazev character. First seen on the Amazo in Season 2, Anatoly introduced Oliver Queen to the Bratva, and that story is currently playing out in the series' flashbacks.

(Trivia: In the comic books, Anatoly Knyazev is the alter ego of Batman villain the KGBeast.)

Donna Smoak

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Donna Smoak may be the most controversial inclusion on this list, as a lot of people, fairly or unfairly, associate her with the feeling that the Smoak family was taking over the series in Season 4. However, Charlotte Ross' first appearances on the show excited a lot of fans, as we finally got to see a little bit of where Felicity came from, and as a bonus, Quentin Lance was finally able to find love -- if for a short time. Ross herself has kept engaged with the fanbase, and is a frequent favorite on Twitter. It is because of those things that Donna merits a place as one of Arrow's unsung heroes.

Baby Sara (Actress Unknown)

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[This entry deleted by Flashpoint. Thanks a lot, Barry!]