To be honest, I'm not so excited by those previews. Pixels hurt me :S
If I had to choose I'd say Pale Gate too.
Why .gif anyway ? .png give more smoothy pictures and it can be converted in .ico as well.
I made a preview of three runes which seemed complicated as icon : Soul Eater, True Wind and Beast Rune.
But, in png, it gives that :
I guess it's not so bad.
Obviously, I didn't work on game-ripped images.
So if you're interested by other runes, I can do bright shield, true earth, true fire, true lightning, true water, pale gate, punishment, runes of beginning and I can probably find Black Sword. Well any runes actually, if I can find a good picture of it (pictures on suikosource are a bit blurred).
It's just to help, but if you don't care about that, no problem ^^