Looks like a Dobson fly. For a better chance at identification, it helps us to know in what kind of environment you saw the insect, and in what part of the world.

I don't think you could have a better picture.
Female Eastern Dobsonfly.
Where I used to work was near a creek with a rocky bottom. In the summer at night, we would occasionally see these fly around the lights on the exterior of the building, sometimes they would come into the building and fly into the lights there.
Their wing beats are pretty noisy when flapping on the light globes overhead.

Here is a link that might be useful: good match