Space Pirate Captain Herlock: Outside Legend - The Endless Odyssey

Another Matsumoto adventure, Cosmo Warrior Zero is another romp through space. Through the eyes of Warrius Zero and the crew of the Karyuu, it's a chase to catch Harlock and the Deathshadow in the name of the greater good. Interesting twists and turns, as the story reveals the real motives behind Harlock's actions, and the strain of the mixed man and machine crew of the Karyuu. Not as gritty or as dramatic as most Leijiverse dramas, what with plenty of silly moments, but entertaining to the end. 

Same creator, and someone with knowledge of one will recognize the art style of the other. Ozuma really feels like Captain Harlock but in a desert, instead of space and with a female commander. However, they aren't reiterations of each other, despite the incredible similarities and both are unique. Ozuma is also a bit more light-hearted and has more animated/emotional characters, whereas the characters in Harlock can sometimes feel static and lacking in personality, development or motive.  

These two series are both amazing space operas, but not only are both made by Matsumoto, Leiji, but the setting as well is quite similar, the feeling you get of the atmosphere from both space battleships the Arcadia and the Yamato sure make up for an amazing ride of an intense story! So if you love space related anime and the work of Leiji then these anime series are definitely for you!  

Both OVA series display a need for a courageous and pure spirit to battle tyranny. New Fist of The North Star shows the failings of religious lunatics while Captain Herlock Endless Odyssey explores fear and hysteria.  

Last Exile and Captain Harlock might not seem similar at first glance, but they actually have a solid link: Alex Rowe, one of the main characters of Last Exile, was written specifically with Captain Harlock in mind. Let us count the ways. Longish hair? Check. Badass cape swishing? Check? Captain of a cool airship/spaceship? Check. Notorious outlaw? Check. Enigmatic and Mysterious? Check. Cool Sword? Well, it's a gun-cane, but check. Waging a one man war against tyrannical overlords/aliens things? Check. There are even more similarities but it would take forever to explain them. Basically, Alex Rowe is an extremely well done, very deep, three dimensional steampunk version of Harlock that is very worthy of the original and fans of Harlock will find in him all the character development and characterization they might have been missing in Endless Odyssey, in Last Exile. While the actual plots of the stories aren't that similar, the Steampunk airships of Last Exile are very like the Space opera-type ships of Harlock, and both have a younger 'hero' playing first-fiddle while the Harlockian characters get to be badass, though by all accounts Claus is a much better hero than Daiba. If you liked Endless Odyssey, check out Last Exile, you'll no doubt find it awesome. If you're a Last Exile fan and want to see the original that gave rise to Alex Rowe, you could do no better than Endless Odyssey as your window to Harlock. read more 

Both have incredibly manly main characters, awesome spaceships and stuff about spirals. What more do you need to know? 

Also by iconic anime and manga creator, Leiji Matsumoto. Rich characters and stories with a signature look and feel. Frequent "cross pollination" of characters between series. 

Both have old-style art and manly leads. 

Along with the original Space Pirate Captain Harlock (1978) this anime has a similar feel. A quirky, endearing crew centered around a heroic, manly captain. Coming of age stories of young kids. Pirates and spaceships! I also believe Ahab's costume design is based off Harlock or other Leiji designs. There are also similar story elements (best friend is the dead head mechanic, captain becomes the foster father). 

Both are Space Operas and dip into the Space Western genres. They lack many similarities in plot and characters (except for a rather uncanny similarity between Harlock and Vicious, appearance-wise, right down to the creepy bird) but through genre alone they are quite related and both have themes of 'space'='freedom'. Harlock is also one of the forerunners of Space Opera anime in general, so any fan of Bebop should see where the influences came from, and any fan of Harlock couldn't do wrong with what's been called one of the best anime ever made EVER.