MOONLIGHT
Yep, you read that right. It's not the most common thing but I've shot with just moonlight so I wanted to at least include it in here so you know it's an option. It takes a bit more planning (you need to catch a full moon, on a cloudless night, in a location that's pretty reflective (lots of light sand, rocks, etc). Just like twilight, since the moon is a more diffused light (it's literally a giant reflector), I shoot it front light to get that luminous look.