Full Metal Alchemist Brotherhood.

There are already some good recommendation in this thread and I will second some of them in my list:

• Baccano!
• Kino’s Journey: Yes, the main character is not an adult, but it handles very mature themes and is similar in feel to Mushishi
• Ghost in the Shell
• Samurai Champloo

Psycho pass.

Golden Kamuy

Violent criminals, samurai, vintage weaponry, cool uniforms, treasure hunts, animal fights, great characters and story. It’s got it all!

Steins Gate

Crazy sci fi adventure in a present day setting, surprise characters and plot twists, loveable characters, and you never know what will happen next.