I just got shown a new one a couple of weeks ago that I like.
Can't remember the japanese for it but here's a try at a description:
from the standard judo grip move the right hand to grip his right lapel from the inside and as high up as you can
then you kind of step/jump with both feet drilling into the ground on the other side (his right side/your left) as you twist and look left as hard as possible.
the choke is almost immediately there.
pretty simple and I've pulled it of once in randori so far. I like's it.