Here is a list of some of the most popular anime anti-heroes:

1. Spike Spiegel (Cowboy Bebop)
2. Roy Mustang (FullMetal Alchemist)
3. Vash the Stampede (Trigun)
4. Alucard (Hellsing)
5. Gon Freecss (Hunter x Hunter)
6. Lelouch vi Britannia (Code Geass)
7. Light Yagami (Death Note)
8. Ken Kaneki (Tokyo Ghoul)
9. Akame (Akame ga Kill!)
10. Killua Zoldyck (Hunter x Hunter)
11. Revy (Black Lagoon)
12. Issei Hyodo (High School DxD)
13. Guts (Berserk)
14. Simon (Gurren Lagann)
15. Hisoka (Hunter x Hunter)

This list is not exhaustive and there are many other popular anime anti-heroes. These characters often blur the line between good and evil, and their actions can be both morally justifiable and unjustifiable, making them some of the most complex and interesting characters in anime.