I like
Rain. If I used it I'd probably use it as a mn with a longer fn, but I like it as a fn too. I also like
Raine but I usually prefer
Rain. (I also prefer
Brook and
Sky to
Brooke and
Skye.
Raine might be the only word name with an e on the end that I actually like...) I know a few people named Rayne. I wouldn't use that spelling but it has grown on me.