What Are The Rarer Varieties Of California Gold Fractional Quarters?

I found myself a pretty nice, clean California Gold Quarter that I've narrowed down the type to being a BG-727, similar to the one down below, which is NOT mine, but it is almost identical, except mine seems to have a much lower grade (somewhere around high XF, I might post it in a different topic), but it seems similar, all the way down to what seems to be a die crack spanning the reverse.



I took a quick look at the variety page, and I was blown away at all the different years and varieties that these interesting fractional coins contained.

So, if anybody knows, what is the rarest variety for the fractional gold quarters?