Damn it, M, this is a really unfair challenge! Anime is epic by its very nature. Take color, add wind, add music and speed lines, get EPIC. Today I watched the entire series: Nabari No Ou
It wasn't even good, but the whole thing was epic. It was all about warring ninja clans. There was tons of wind. I couldn't stop watching, even when I kept thinking about how they did nothing to set up the plot or the characters. They just relied on the typical character tropes for 26 episodes. There was nothing interesting about it at all.
Afterwards, I saw that Most Epic Scene was today's challenge, and I thought, take anything, add feudal Japan, warring clans, some kind of hidden power/magic get epic. So speaking of feudal Japan, warring clans and powers, I always liked this scene from, you guessed it, Mirage of Blaze (around 20:50):
When a lovesick, desperate, obsessed Naoe decides to fuse himself and his Lord into a mirror and cast them to the bottom of the lake where they can live together eternally, basically a murder/suicide pact for the immortal. Oddly, this may be one of the least epic scenes in the entire anime, which is very, very, very epic all around.