Most of the anime series have a lot of momentum because of the series that they're based on. If they come from a manga series that has already got a ton of love, their success is basically written in the stars. Without a popular manga and a built-in fan base, manga-less anime series need to be even better to reach the same level of acclaim.

There are a few series that were able to pull off this impressive feat. When they're released, they're relatively unknown because they aren't based on anything. These series can still become all-time greats, and the fact that they don't have an underlying manga series they need to be loyal to gives them creative freedom that manga-inspired anime adaptations just don't have.

8 Cyberpunk: Edgerunners

Animated By Trigger, Based on the Cyberpunk 2077 Video Game By CD Projekt Red (Set in the Cyberpunk Universe Created By Mike Pondsmith)

Cyberpunk: Edgerunners is an emotional roller coaster that's the perfect pick for anyone looking to watch an entire series that's less than 12 episodes long. It also doesn't have a manga, Webtoon, or manhwa that it's based on. Instead, Cyberpunk: Edgerunners is based off of the Cyberpunk 2077 video game, which is based on Mike Pondsmith's amazing Cyberpunk universe.

Cyberpunk: Edgerunners is filled with action, romance, and despair in equal measure. The series stars David Martinez, a teenager in a dystopian society that is less than welcoming. When he meets Lucy, his world is turned upside down. He's introduced to the underside of Night City, finds his own gang of Edgerunners, and falls hopelessly in love with Lucy. It's an amazing, concise story with a brutal ending that couldn't have been any better.

7 Steins;Gate

Animated By White Fox, Based on the Visual Novel Game by 5pb

Steins;Gate is widely considered to be one of the best anime series ever made, and it wasn't based off of an underlying manga. Steins;Gate was initially a visual novel video game developed by 5pb, spawning an anime series, a manga, and so much more. It's a series that provides its viewers with more questions than answers in the best way possible.

Steins;Gate stars Okabe "Okarin" Rintaro as one of the few self-proclaimed genius scientists who is actually a genius. He invents time travel almost accidentally, setting a series of events into motion even his genius could never have seen coming. Steins;Gate is one of the smartest series ever made, making for a great watch for anyone who wants to deal with some of the heaviest themes in anime.

6 Cowboy Bebop

Original Anime Series Created By Sunrise

Cowboy Bebop is a near-legendary series that helped bring anime to the West. It was the first anime series to ever be aired on Adult Swim, ushering in a new art form for American audiences that would only grow from there. Cowboy Bebop is much more than a series that brought anime to the West from Japan: it's an amazing series filled with complex characters, a succinct run time, and one of the most interesting plots around.

Cowboy Bebop is a Japanese neo-noir space Western starring Spike Spiegel as a bounty hunter pursuing criminals all over the Solar System. He's one of the best around, and with the rest of the crew of the Bebop around him, there's not much he can't do. The story isn't that straightforward though, as there are dozens of twists and turns that define the series and create an intriguing environment just waiting to be explored.

5 Darling in the FranXX

An Anime Original Series Produced by A-1 Pictures and Trigger, Animated By Trigger and CloverWorks

Darling in the FranXX is a fever dream of an anime series in the best way possible. While the series is centered on one of the worst tropes in anime (child soldiers), it is so much more than its premise. It's a wonderful series filled with hope, incredible action sequences, and some of the best mech battles around.

Darling in the FranXX stars Squad 13 of Plantation 13. They're a group of some of the strongest pilots in the series, but one of their best, Hiro, isn't able to partner up with anyone successfully. That all changes when Zero-Two enters the mix. She's a dangerous, unknown figure within their group. With her help, however, Hiro is finally able to pilot the titular FranXX. They work together to make one of anime's cutest duos in a series that never had a manga to begin with.

4 Samurai Champloo

An Original Series Animated By Studio Manglobe

Samurai Champloo is a cult class anime series that came from the same director of Cowboy Bebop, the current hit series Lazarus, and Terror in Resonance. Samurai Champloo's setting is infectiously simple: what if hip-hop played a prominent role in the Edo period of Japan? It's a fun, quirky concept that makes for one of the best anime series that runs for less than 30 episodes.

Samurai Champloo stars a reluctant trio including Fuu, a tea waitress, Mugen, an outlaw, and Jin, a ronin. The three work together to find a samurai who smells of sunflowers. It's an entertaining series from start to finish, and while it can be a relatively lighthearted series, it still deals with pretty serious themes. Samurai Champloo tackles themes of death, acceptance, and identity with poise and grace, and it's another series that proves an anime doesn't need a manga to be exceptional.

3 Gurren Lagann

Original Anime Series Animated By Gainax, Co-Produced by Aniplex and Konami

Gurren Lagann is thrilling, heart-breaking, and thought-provoking all at once, and it came well before any manga. It's one of the best kaiju anime series of all time, starring two of the most lovable characters around. Simon and Kamina take center stage in Gurren Lagann as they look to leave their underground home, explore the dangerous surface world, and defeat the enemies that have been oppressing them for years.

Gurren Lagann is one of those series that feels like a dream. It's so out there tonally that it can't easily be called light or dark. It's silly, serious, funny, action-packed, and so much more. It has one of the saddest turns in anime and tells an amazing story in no time at all.

2 Angel Beats!

An Original Series Animated By P.A. Works

Angel Beats! is another one of the best anime series that runs for less than 20 episodes. It also came before a manga, so anime-only enjoyers won't have to be worried about manga readers spoiling their experience. Angel Beats! stars a group of kids who have died, and are reincarnated into a new world that resembles a normal Japanese high school.

Their world is anything but normal, however, as they uncover a series of twists and turns that add a serious level of depth to their new lives. Angel Beats! is a deeply philosophical anime masquerading itself as a simple isekai series. It does an exceptional job of hiding its true intentions during the first few episodes, creating a great surprise for anyone unfamiliar with the story.

1 Neon Genesis Evangelion

Original Anime Series Produced By Gainax, Animated By Tatsunoko, and Directed By Hideaki Anno

Neon Genesis Evangelion is one of the most critically acclaimed anime series of all time. It's also a staple of the anime genre and a series most people will point to so that they can show how deep their interest in the art form runs. Neon Genesis is one of the weirdest anime series ever, and it's this weirdness that makes the series stand out from everything around it.

Neon Genesis Evangelion is a series so unique, it would have been held back if it were based on a manga. It's a mech anime, a kaiju anime, a science-fiction anime, and so much more wrapped up into an incredibly tight 26-episode run. It's also a series that's incredibly hard to describe in words, as any basic description takes away from the deep, esoteric feeling viewers get when they have a chance to sit down with this masterpiece.