There's the Zatoichi series. The first, The Tale of Zatoichi (1962) is required but I gave up after the first three. @falidorn@lemmy.world mentioned that Kazuo Miyagawa was the cinematographer for some of them in this thread.

The Sword of Doom is a classic. Same for Harakiri. Maybe Bushido: The Cruel Code of the Samurai, too (depends on one's tastes). If you don't want to get stuck in the 60s, Twilight Samurai is more modern.

I'm forgetting some that are worth a mention, but I'm totally skipping some titles I think are just 'meh'.

I enjoyed 13 Assasins, it's worth a viewing.

The Samurai Trilogy is great. It's a fictionalized telling of Musashi Miyamoto's life based on a serial published in a Japanese newspaper between 1935 and 1939 (and was later released as the novel "Musashi: An Epic Novel of the Samurai Era"). It was directed by Hiroshi Inagaki, and stars Toshiro Mifune as Miyamoto. I re-watch the trilogy once every couple of years. It's pretty solid.

47 Ronin and Shōgun.

Shōgun is a miniseries but it’s awesome.

The Lone Wolf and Cub series for sure. Maybe start the traditional way with the "americanized" "compilation" Shogun Assassin.

On the modern side, rza's Man With The Iron Fist is worthwhile, along with the Kill Bills.

There is a lot of overlap with kung fu. I would recommend 36 chambers of Shaolin as a good entry point there.

Shinya Tsukamoto's 2018 film Killing is a great, tense story that both plays into and undermines some of the tropes of samurai films. It's a bit brutal at times, and also amusing in that wry way that Tsukamoto is so good at.

The Last Samurai!

Kek